Sociophysics: A review of Galam models
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paper_title: Spontaneous Coalition Forming. Why Some Are Stable?

paper_content:

A model to describe the spontaneous formation of military and economic coalitions among a group of countries is proposed using spin glass theory. Between each couple of countries, there exists a bond exchange coupling which is either zero, cooperative or conflicting. It depends on their common history, specific nature, and cannot be varied. Then, given a frozen random bond distribution, coalitions are found to spontaneously form. However they are also unstable making the system very disordered. Countries shift coalitions all the time. Only the setting of macro extra national coalition are shown to stabilize alliances among countries. The model gives new light on the recent instabilities produced in Eastern Europe by the Warsow pact dissolution at odd to the previous communist stability. Current European stability is also discussed with respect to the European Union construction.
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paper_title: Rational group decision making: a random field Ising model at

paper_content:

A modified version of a finite random field Ising ferromagnetic model in an external magnetic field at zero temperature is presented to describe group decision making. Fields may have a non-zero average. A postulate of minimum inter-individual conflicts is assumed. Interactions then produce a group polarization along one very choice which is however randomly selected. A small external social pressure is shown to have a drastic effect on the polarization. Individual bias related to personal backgrounds, cultural values and past experiences are introduced via quenched local competing fields. They are shown to be instrumental in generating a larger spectrum of collective new choices beyond initial ones. In particular, compromise is found to results from the existence of individual competing bias. Conflict is shown to weaken group polarization. The model yields new psychosociological insights about consensus and compromise in groups.
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paper_title: Political paradoxes of majority rule voting and hierarchical systems

paper_content:

The use of majority rule voting is believed to be instrumental to establish democratic operating of political organizations. However in this work it is shown that, while applied to hierarchical systems, it leads to political paradoxes. To substantiate these findings a model to construct self-directed pyramidal structures from bottom up to the top is presented. Using majority rules it is shown that a minority and even a majority can be systematically self-eliminated from top leadership, provided the hierarchy has a minimal number of levels. In some cases, 70% of the population is found to have zero representation after 6 hierarchical levels. Results are discussed with respect to internal operating of political organizations.
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paper_title: Local dynamics vs.?social mechanisms: A unifying frame

paper_content:

We present a general sequential probabilistic frame, which extends a series of earlier opinion dynamics models. In addition, it orders and classifies all of the existing two-state spin systems. The scheme operates via local updates where a majority rule is applied differently in each possible configuration of a local group. It is weighted by a local probability which is a function of the local value of the order parameter, i.e., the majority-to-minority ratio. The system is thus driven from one equilibrium state into another equilibrium state till no collective change occurs. A phase diagram can thus be constructed. It has two phases, one where the collective opinion ends up broken along one opinion, and another with an even coexistence of both opinions. Two different regimes, monotonic and dampened oscillatory, are found for the coexistence phase. At the phase transition local probabilities conserve the density of opinions and reproduce the collective dynamics of the Voter model. The essential behavior of all existing discrete two-state models (Galam, Sznajd, Ochrombel, Stauffer, Krapivsky-Redner, Mobilia-Redner, Behera-Schweitzer, Slanina-Lavicka, Sanchez ...) is recovered and found to depart from each other only in the value of their local probabilities. Corresponding simulations are discussed. It is concluded that one should not judge from the above model results the validity of their respective psycho-social assumptions.
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paper_title: Towards a theory of collective phenomena. III: Conflicts and forms of power

paper_content:

This paper further develops a new theory of power advanced by the authors in two previous papers (Galam and Moscovici, 1991, 1994). According to this theory power results from the build up of conflicts within a group, these conflicts requiring a degree of organizational complexity which is itself a decreasing function of group size. Within this approach, power appears to be a composite of three qualitatively different powers, institutional, generative and ecological. Levels and relationships among these forms of power are considered as a function of the diversity of the group. There exist also three states of organization associated with power evolution. At the group initial stage is the paradigmatic state. Creation and inclusion of conflicts are accomplished in the transitional state through the building of complexity. At a critical value of diversity, the group moves into the agonal state in which institutional power vanishes simultaneously with the fusion of generative and ecological powers
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paper_title: From 2000 Bush-Gore to 2006 Italian elections: Voting at fifty-fifty and the Contrarian Effect

paper_content:

A sociophysical model for opinion dynamics is shown to embody a series of recent western hung national votes all set at the unexpected and very improbable edge of a fifty-fifty score. It started with the Bush–Gore 2000 American presidential election, followed by the 2002 Stoiber–Schroder, then the 2005 Schroder–Merkel German elections, and finally the 2006 Prodi-Berlusconi Italian elections. In each case, the country was facing drastic choices, the running competing parties were advocating very different programs and millions of voters were involved. Moreover, polls were given a substantial margin for the predicted winner. While all these events were perceived as accidental and isolated, our model suggests that indeed they are deterministic and obey to one single universal phenomena associated to the effect of contrarian behavior on the dynamics of opinion forming. The not hung Bush–Kerry 2004 presidential election is shown to belong to the same universal frame. To conclude, the existence of contrarians hints at the repetition of hung elections in the near future.
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paper_title: Modeling rumors: The no plane pentagon french hoax case

paper_content:

The recent astonishing wide adhesion of French people to the rumor claiming ‘No plane did crash on the Pentagon on September 11’, is given a generic explanation in terms of a model of minority opinion spreading. Using a majority rule reaction–diffusion dynamics, a rumor is shown to invade for sure a social group provided it fulfills simultaneously two criteria. First it must initiate with a support beyond some critical threshold which however, turns out to be always very low. Then it has to be consistent with some larger collective social paradigm of the group. Otherwise it just dies out. Both conditions were satisfied in the French case with the associated book sold at more than 200 000 copies in just a few days. The rumor was stopped by the firm stand of most newspaper editors stating it is nonsense. Such an incredible social dynamics is shown to result naturally from an open and free public debate among friends and colleagues. Each one searching for the truth sincerely on a free will basis and without individual biases. The polarization process appears also to be very quick in agreement with reality. It is a very strong anti-democratic reversal of opinion although made quite democratically. The model may apply to a large range of rumors.
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paper_title: On reducing terrorism power: a hint from physics

paper_content:

The September 11 attack on the US has revealed an unprecedented terrorism worldwide range of destruction. Recently, it has been related to the percolation of worldwide spread passive supporters. This scheme puts the suppression of the percolation effect as the major strategic issue in the fight against terrorism. Accordingly the world density of passive supporters should be reduced below the percolation threshold. In terms of solid policy, it means to neutralize millions of random passive supporters, which is contrary to ethics and out of any sound practical scheme. Given this impossibility we suggest instead a new strategic scheme to act directly on the value of the terrorism percolation threshold itself without harming the passive supporters. Accordingly we identify the space hosting the percolation phenomenon to be a multi-dimensional virtual social space which extends the ground earth surface to include the various independent terrorist-fighting goals. The associated percolating cluster is then found to create long-range ground connections to terrorism activity. We are thus able to modify the percolation threshold pc in the virtual space to reach p<pc by decreasing the social space dimension, leaving the density p unchanged. At once that would break down the associated world terrorism network to a family of unconnected finite-size clusters. The current world terrorism threat would thus shrink immediately and spontaneously to a local geographic problem. There, military action would become limited and efficient.
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paper_title: Opinion dynamics in a three-choice system

paper_content:

We generalize Galam’s model of opinion spreading by introducing three competing choices. At each update, the population is randomly divided in groups of three agents, whose members adopt the opinion of the local majority. In the case of a tie, the local group adopts opinion A, B or C with probabilities α, β and (1-α-β) respectively. We derive the associated phase diagrams and dynamics by both analytical means and simulations. Polarization is always reached within very short time scales. We point out situations in which an initially very small minority opinion can invade the whole system.
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paper_title: Application of statistical physics to politics

paper_content:

The concept and technics of real space renormalization group are applied to study majority rule voting in hierarchical structures. It is found that democratic voting can lead to totalitarianism by keeping in power a small minority. Conditions of this paradox are analyzed and singled out. Indeed majority rule produces critical thresholds to absolute power. Values of these thresholds can vary from 50% up to at least 77%. The associated underlying mechanism could provide an explanation for both former apparent eternity of communist leaderships and their sudden collapse.
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paper_title: Universality of Group Decision Making

paper_content:

Group decision making is assumed to obey some universal features which are independent of both the social nature of the group making the decision and the nature of the decision itself. On this basis a simple magnetic like model is built. Pair interactions are introduced to measure the degree of exchange among individuals while discussing. An external uniform field is included to account for a possible pressure from outside. Individual biases with respect to the issue at stake are also included using local random fields. A unique postulate of minimum conflict is assumed. The model is then solved with emphasize on its psycho-sociological implications. Counter-intuitive results are obtained. At this stage no new physical technicality is involved. Instead, the full psycho-sociological implications of the model are drawn. Few cases are then detailed to enlight them.
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paper_title: Global Physics: From Percolation to Terrorism, Guerilla Warfare and Clandestine Activities

paper_content:

The September 11 attack on the US has revealed an unprecedented terrorism with worldwide range of destruction. It is argued to result from the first worldwide percolation of passive supporters. They are people sympathetic to the terrorism cause but without being involved with it. They just do not oppose it in case they could. This scheme puts suppression of the percolation as the major strategic issue in the fight against terrorism. Acting on the population is shown to be useless. Instead a new strategic scheme is suggested to increase the terrorism percolation threshold and in turn suppress the percolation. The relevant associated space is identified as a multi-dimensional social space including both the ground earth surface and all various independent flags displayed by the terrorist group. Some hints are given on how to shrink the geographical spreading of terrorism threat. The model apply to a large spectrum of clandestine activities including guerilla warfare as well as tax evasion, corruption, illegal gambling, illegal prostitution and black markets.
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paper_title: From Individual Choice to Group Decision Making

paper_content:

Some universal features are independent of both the social nature of the individuals making the decision and the nature of the decision itself. On this basis a simple magnet like model is built. Pair interactions are introduced to measure the degree of exchange among individuals while discussing. An external uniform field is included to account for a possible pressure from outside. Individual biases with respect to the issue at stake are also included using local random fields. A unique postulate of minimum conflict is assumed. The model is then solved with emphasis on its psycho-sociological implications. Counter-intuitive results are obtained. At this stage no new physical technicality is involved. Instead the full psycho-sociological implications of the model are drawn. Few cases are then detailed to enlight them. In addition, several numerical experiments based on our model are shown to give both an insight on the dynamics of the model and suggest further research directions.
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paper_title: An evolution theory in finite size systems

paper_content:

A new model of evolution is presented for finite size systems. Conditions under which a minority species can emerge, spread and stabilize to a macroscopic size are studied. It is found that space organization is instrumental in addition to a qualitative advantage. Some peculiar topologies ensure the overcome of the initial majority species. However the probability of such local clusters is very small and depend strongly on the system size. A probabilistic phase diagram is obtained for small sizes. It reduces to a trivial situation in the thermodynamic limit, thus indicating the importance of dealing with finite systems in evolution problems. Results are discussed with respect to both Darwin and punctuated equilibria theories.
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paper_title: Killer Geometries in Competing Species Dynamics

paper_content:

We discuss a cellular automata model to study the competition between an emergent better fitted species against an existing majority species. The model implements local fights among small group of individuals and a synchronous random walk on a 2D lattice. The faith of the system, i.e., the spreading or disappearance of the species is determined by their initial density and fight frequency. The initial density of the emergent species has to be higher than a critical threshold for total spreading but this value depends in a non-trivial way on the fight frequency. Below the threshold any better adapted species disappears showing that a qualitative advantage is not enough for a minority to win. No strategy is involved but spatial organization turns out to be crucial. For instance, at minority densities of zero measure some very rare local geometries which occur by chance are found to be killer geometries. Once set they lead with high probability to the total destruction of the preexisting majority species. The occurrence rate of these killer geometries is a function of the system size. This model may apply to a large spectrum of competing groups like smoker–non smoker, opinion forming, diffusion of innovation setting of industrial standards, species evolution, epidemic spreading and cancer growth.
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paper_title: Fragmentation versus stability in bimodal coalitions

paper_content:

Competing bimodal coalitions among a group of actors are discussed. First, a model from political sciences is revisited. Most of the model statements are found not to be contained in the model. Second, a new coalition model is built. It accounts for local versus global alignment with respect to the joining of a coalition. The existence of two competing world coaltions is found to yield one unique stable distribution of actors. On the opposite a unique world leadership allows the emergence of unstable relationships. In parallel to regular actors which have a clear coalition choice, ``neutral"``frustrated"and ``risky"actors are produced. The cold war organisation after world war II is shown to be rather stable. The emergence of a fragmentation process from eastern group disappearance is explained as well as continuing western group stability. Some hints are obtained about possible policies to stabilize world nation relationships. European construction is analyzed with respect to european stability. Chinese stability is also discussed.
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paper_title: Comment on “A landscape theory of aggregation”

paper_content:

The problem of aggregation processes in alignments is the subject of a paper published recently in a statistical physics journal. Two models are presented and discussed in that paper. First, the energy landscape model proposed by Robert Axelrod and D. Scott Bennett (this Journal, 23 (1993), 211–33) is analysed. The model is shown not to include most of its claimed results. Then a second model is presented to reformulate the problem correctly within statistical physics and to extend it beyond the initial Axelrod-Bennett analogy. ::: Serge Galam, ‘Fragmentation Versus Stability in Bimodal Coalitions’, Physica A , 230 (1966), 174–88.
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paper_title: The role of inflexible minorities in the breaking of democratic opinion dynamics

paper_content:

We study the effect of inflexible agents on two state opinion dynamics. The model operates via repeated local updates of random grouping of agents. While floater agents do eventually flip their opinion to follow the local majority, inflexible agents keep their opinion always unchanged. It is a quenched individual opinion. In the bare model (no inflexibles), a separator at 50% drives the dynamics towards either one of two pure attractors, each associated with a full polarization along one of the opinions. The initial majority wins. The existence of inflexibles for only one of the two opinions is found to shift the separator at a lower value than 50% in favor of that side. Moreover it creates an incompressible minority around the inflexibles, one of the pure attractors becoming a mixed phase attractor. In addition above a threshold of 17% inflexibles make their side sure of winning whatever the initial conditions are. The inflexible minority wins. An equal presence of inflexibles on both sides restores the balanced dynamics with again a separator at 50% and now two mixed phase attractors on each side. Nevertheless, beyond 25% the dynamics is reversed with a unique attractor at a 50–50 stable equilibrium. But a very small advantage in inflexibles results in a decisive lowering of the separator at the advantage of the corresponding opinion. A few percent advantage does guarantee to become majority with one single attractor. The model is solved exhaustedly for groups of size 3.
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paper_title: Majority rule, hierarchical structures, and democratic totalitarianism: a statistical approach

paper_content:

Abstract An alternative model to the formation of pyramidal structures is presented in the framework of social systems. The population is assumed to be distributed between two social orientations G and H with respective probabilities p 0 and (1 − p 0 ). Instead of starting the hierarchy with a given H -orientation at the top and then going downwards in a deterministic way, the hierarchy is initiated randomly at the bottom from the surrounding population. Every level is then selected from the one underneath using the principle of majority rule. The hierarchy is thus self-oriented at the top. It is shown how such self-oriented hierarchies are always H -oriented provided they have a minimal number of levels which is determined by the value of p 0 . Their stability is studied against increases in p 0 . An ideal transition to G -self-oriented hierarchies is obtained.
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paper_title: Stability of leadership in bottom-up hierarchical organizations

paper_content:

The stability of a leadership against a growing internal opposition is studied in bottom-up hierarchical organizations. Using a very simple model with bottom-up majority rule voting, the dynamics of power distribution at the various hierarchical levels is calculated within a probabilistic framework. Given a leadership at the top, the opposition weight from the hierarchy bottom is shown to fall off quickly while climbing up the hierarchy. It reaches zero after only a few hierarchical levels. Indeed the voting process is found to obey a threshold dynamics with a deterministic top outcome. Accordingly the leadership may stay stable against very large amplitude increases in the opposition at the bottom level. An opposition can thus grow steadily from few percent up to seventy seven percent with not one a single change at the elected top level. However and in contrast, from one election to another, in the vicinity of the threshold, less than a one percent additional shift at the bottom level can drive a drastic and brutal change at the top. The opposition topples the current leadership at once. In addition to analytical formulas, results from a large scale simulation are presented. The results may shed a new light on management architectures as well as on alert systems. They could also provide some
---
paper_title: Social paradoxes of majority rule voting and renormalization group

paper_content:

Real-space renormalization group ideas are used to study a voting problem in political science. A model to construct self-directed pyramidal structures from bottom up to the top is presented. Using majority rules, it is shown that a minority and even a majority can be systematically self-eliminated from top leadership, provided the hierarchy has a minimal number of levels. In some cases, 70% of the population is found to have zero representation after six hierarchical levels. Results are discussed with respect to the internal operation of political organizations.
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paper_title: Optimizing Conflicts in the Formation of Strategic Alliances

paper_content:

Abstract:Coalition setting among a set of actors (countries, firms, individuals) is studied using concepts from the theory of spin glasses. Given the distribution of respective bilateral propensities to either cooperation or conflict, the phenomenon of local aggregation is modeled. In particular the number of coalitions is determined according to a minimum conflict principle. It is found not to be always two. Along these lines, previous studies are revisited and are found not to be consistent with their own principles. The model is then used to describe the fragmentation of former Yugoslavia. Results are compared to the actual situation.
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paper_title: FASHION, NOVELTY AND OPTIMALITY: An application from Physics

paper_content:

We apply a physical-based model to describe the clothes fashion market. Every time a new outlet appears on the market, it can invade the market under certain specific conditions. Hence, the “old” outlet can be completely dominated and disappears. Each creator competes for a finite population of agents. Fashion phenomena are shown to result from a collective phenomenon produced by local individual imitation effects. We assume that, in each step of the imitation process, agents only interact with a subset rather than with the whole set of agents. People are actually more likely to influence (and be influenced by) their close “neighbors”. Accordingly, we discuss which strategy is best fitted for new producers when people are either simply organized into anonymous reference groups or when they are organized in social groups hierarchically ordered. While counterfeits are shown to reinforce the first strategy, creating social leaders can permit to avoid them.
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paper_title: Towards a theory of collective phenomena. II: Conformity and power

paper_content:

A new theory of power is presented using the concept of symmetry breakdown in small and large groups. Power appears to result from the building up of conflicts within the group. Introduction and support of these conflicts requires an internal organization of the group. The organization-associated complexity is a decreasing function of group size. Thus small groups have more difficulties in generating internal conflicts than large ones. This group dynamic is characterized by two states which are different in their nature. The group is first built within the paradigmatic state aimed to determine and reproduce group conformity The group challenge is then to reach the transitional state which enriches the group possibilities through the inclusion and stabilization of internal conflicts.
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paper_title: Towards a theory of collective phenomena: Consensus and attitude changes in groups

paper_content:

This study presents the outline of a model for collective phenomena. A symmetry-breaking model combines a number of well-established social psychology hypotheses with recent concepts of statistical physics. Specifically we start out from the regularities obtained in studies on the polarization of attitudes and decisions. From a strictly logical point of view, it is immediately clear that aggregation effects must be analysed separately from group effects as such. The conceptual analysis of the assumed mechanisms reveals that when we deal with phenomena that have until now been designated as polarization phenomena, we are faced not with a single phenomenon, as was believed hitherto, but with a whole class of phenomena. For this reason it would be appropriate to deal with them differentially both from an empirical and from a theoretical point of view. It is possible to show, moreover, that in principle polarization is a direct function of interaction and, beyond a critical threshold an inverse function of the differentiation between group members. A certain number of verifiable conjectures are presented on the basis of physio-mathematical-psychological considerations. It is to be hoped that these theoretical outlines will make it possible to give a new lease on life to a field of research that has established solid facts, but that became trapped in a dead-end road, for lack of a sufficiently broad analysis.
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paper_title: Dictatorship from majority rule voting

paper_content:

Abstract:Majority rule voting in a multi-level system is studied using tools from the physics of disorder. We are not dealing with nation-wide general elections but rather with hierarchical organisations made of small committees. While in theory, for a two candidate election, the critical threshold to absolute power is , the usual existence of some local and reasonable bias makes it asymmetric, transforming a democratic system in effect to a dictatorship. The underlying dynamics of this democratic self-elimination is studied using a simulation which visualizes the full process. In addition the effect of non-voting persons (abstention, sickness, apathy) is also studied. It is found to have an additional drastic effect on the asymmetry of the threshold value to power. Some possible applications are mentioned.
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paper_title: Threshold Phenomena versus Killer Clusters in Bimodal Competion for Standards

paper_content:

Given an individually used standard on a territory we study the conditions for total spreading of a new emergent better fitted competing standard. The associated dynamics is monitored by local competing updating which occurs at random among a few individuals. The analysis is done using a cellular automata model within a two-dimensional lattice with synchronous random walk. Starting from an initial density of the new standard the associated density evolution is studied using groups of four individuals each. For each local update the outcome goes along the local majority within the group. However in case of a tie, the better fitted standard wins. Updates may happen at each diffusive step according to some fixed probability. For every value of that probability a critical threshold, in the initial new emergent standard density, is found to determine its total either disappearance or spreading making the process a threshold phenomenon. Nevertheless it turns out that even at a zero density measure of the new emergent standard there exits some peculiar killer clusters of it which have a non zero probability to grow and invade the whole system. At the same time the occurrence of such killer clusters is a very rare event and is a function of the system size. Application of the model to a large spectrum of competing dynamics is discussed. It includes the smoker-non smoker fight, opinion forming, diffusion of innovation, species evolution, epidemic spreading and cancer growth.
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paper_title: Sociophysics: A mean behavior model for the process of strike

paper_content:

Plant for the treatment and the oxidation of antimony minerals, wherein an antimony mineral with any granulometry and humidity, eventually crushed, is carried by a hot gaseous stream, subjected to milling, drying, subsequent separations and then introduced in a rotary kiln in a state of extreme subdivision and oxidized dispersed in a gaseous compressed oxidizing stream.
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paper_title: Real space renormalization group and totalitarian paradox of majority rule voting

paper_content:

The effect of majority rule voting in hierarchical structures is studied using the basic concepts from real space renormalization group. It shows in particular that a huge majority can be self-eliminated while climbing up the hierarchy levels. This majority democratic self-elimination articulates around the existence of fixed points in the voting flow. An unstable fixed point determines the critical threshold to full and total power. It can be varied from 50% up to 77% of initial support. Our model could shed new light on the last century eastern European communist collapse.
---
paper_title: Political paradoxes of majority rule voting and hierarchical systems

paper_content:

The use of majority rule voting is believed to be instrumental to establish democratic operating of political organizations. However in this work it is shown that, while applied to hierarchical systems, it leads to political paradoxes. To substantiate these findings a model to construct self-directed pyramidal structures from bottom up to the top is presented. Using majority rules it is shown that a minority and even a majority can be systematically self-eliminated from top leadership, provided the hierarchy has a minimal number of levels. In some cases, 70% of the population is found to have zero representation after 6 hierarchical levels. Results are discussed with respect to internal operating of political organizations.
---
paper_title: Application of statistical physics to politics

paper_content:

The concept and technics of real space renormalization group are applied to study majority rule voting in hierarchical structures. It is found that democratic voting can lead to totalitarianism by keeping in power a small minority. Conditions of this paradox are analyzed and singled out. Indeed majority rule produces critical thresholds to absolute power. Values of these thresholds can vary from 50% up to at least 77%. The associated underlying mechanism could provide an explanation for both former apparent eternity of communist leaderships and their sudden collapse.
---
paper_title: Majority rule, hierarchical structures, and democratic totalitarianism: a statistical approach

paper_content:

Abstract An alternative model to the formation of pyramidal structures is presented in the framework of social systems. The population is assumed to be distributed between two social orientations G and H with respective probabilities p 0 and (1 − p 0 ). Instead of starting the hierarchy with a given H -orientation at the top and then going downwards in a deterministic way, the hierarchy is initiated randomly at the bottom from the surrounding population. Every level is then selected from the one underneath using the principle of majority rule. The hierarchy is thus self-oriented at the top. It is shown how such self-oriented hierarchies are always H -oriented provided they have a minimal number of levels which is determined by the value of p 0 . Their stability is studied against increases in p 0 . An ideal transition to G -self-oriented hierarchies is obtained.
---
paper_title: Stability of leadership in bottom-up hierarchical organizations

paper_content:

The stability of a leadership against a growing internal opposition is studied in bottom-up hierarchical organizations. Using a very simple model with bottom-up majority rule voting, the dynamics of power distribution at the various hierarchical levels is calculated within a probabilistic framework. Given a leadership at the top, the opposition weight from the hierarchy bottom is shown to fall off quickly while climbing up the hierarchy. It reaches zero after only a few hierarchical levels. Indeed the voting process is found to obey a threshold dynamics with a deterministic top outcome. Accordingly the leadership may stay stable against very large amplitude increases in the opposition at the bottom level. An opposition can thus grow steadily from few percent up to seventy seven percent with not one a single change at the elected top level. However and in contrast, from one election to another, in the vicinity of the threshold, less than a one percent additional shift at the bottom level can drive a drastic and brutal change at the top. The opposition topples the current leadership at once. In addition to analytical formulas, results from a large scale simulation are presented. The results may shed a new light on management architectures as well as on alert systems. They could also provide some
---
paper_title: Social paradoxes of majority rule voting and renormalization group

paper_content:

Real-space renormalization group ideas are used to study a voting problem in political science. A model to construct self-directed pyramidal structures from bottom up to the top is presented. Using majority rules, it is shown that a minority and even a majority can be systematically self-eliminated from top leadership, provided the hierarchy has a minimal number of levels. In some cases, 70% of the population is found to have zero representation after six hierarchical levels. Results are discussed with respect to the internal operation of political organizations.
---
paper_title: Dictatorship from majority rule voting

paper_content:

Abstract:Majority rule voting in a multi-level system is studied using tools from the physics of disorder. We are not dealing with nation-wide general elections but rather with hierarchical organisations made of small committees. While in theory, for a two candidate election, the critical threshold to absolute power is , the usual existence of some local and reasonable bias makes it asymmetric, transforming a democratic system in effect to a dictatorship. The underlying dynamics of this democratic self-elimination is studied using a simulation which visualizes the full process. In addition the effect of non-voting persons (abstention, sickness, apathy) is also studied. It is found to have an additional drastic effect on the asymmetry of the threshold value to power. Some possible applications are mentioned.
---
paper_title: Real space renormalization group and totalitarian paradox of majority rule voting

paper_content:

The effect of majority rule voting in hierarchical structures is studied using the basic concepts from real space renormalization group. It shows in particular that a huge majority can be self-eliminated while climbing up the hierarchy levels. This majority democratic self-elimination articulates around the existence of fixed points in the voting flow. An unstable fixed point determines the critical threshold to full and total power. It can be varied from 50% up to 77% of initial support. Our model could shed new light on the last century eastern European communist collapse.
---
paper_title: Application of statistical physics to politics

paper_content:

The concept and technics of real space renormalization group are applied to study majority rule voting in hierarchical structures. It is found that democratic voting can lead to totalitarianism by keeping in power a small minority. Conditions of this paradox are analyzed and singled out. Indeed majority rule produces critical thresholds to absolute power. Values of these thresholds can vary from 50% up to at least 77%. The associated underlying mechanism could provide an explanation for both former apparent eternity of communist leaderships and their sudden collapse.
---
paper_title: Majority rule, hierarchical structures, and democratic totalitarianism: a statistical approach

paper_content:

Abstract An alternative model to the formation of pyramidal structures is presented in the framework of social systems. The population is assumed to be distributed between two social orientations G and H with respective probabilities p 0 and (1 − p 0 ). Instead of starting the hierarchy with a given H -orientation at the top and then going downwards in a deterministic way, the hierarchy is initiated randomly at the bottom from the surrounding population. Every level is then selected from the one underneath using the principle of majority rule. The hierarchy is thus self-oriented at the top. It is shown how such self-oriented hierarchies are always H -oriented provided they have a minimal number of levels which is determined by the value of p 0 . Their stability is studied against increases in p 0 . An ideal transition to G -self-oriented hierarchies is obtained.
---
paper_title: Social paradoxes of majority rule voting and renormalization group

paper_content:

Real-space renormalization group ideas are used to study a voting problem in political science. A model to construct self-directed pyramidal structures from bottom up to the top is presented. Using majority rules, it is shown that a minority and even a majority can be systematically self-eliminated from top leadership, provided the hierarchy has a minimal number of levels. In some cases, 70% of the population is found to have zero representation after six hierarchical levels. Results are discussed with respect to the internal operation of political organizations.
---
paper_title: Real space renormalization group and totalitarian paradox of majority rule voting

paper_content:

The effect of majority rule voting in hierarchical structures is studied using the basic concepts from real space renormalization group. It shows in particular that a huge majority can be self-eliminated while climbing up the hierarchy levels. This majority democratic self-elimination articulates around the existence of fixed points in the voting flow. An unstable fixed point determines the critical threshold to full and total power. It can be varied from 50% up to 77% of initial support. Our model could shed new light on the last century eastern European communist collapse.
---
paper_title: Application of statistical physics to politics

paper_content:

The concept and technics of real space renormalization group are applied to study majority rule voting in hierarchical structures. It is found that democratic voting can lead to totalitarianism by keeping in power a small minority. Conditions of this paradox are analyzed and singled out. Indeed majority rule produces critical thresholds to absolute power. Values of these thresholds can vary from 50% up to at least 77%. The associated underlying mechanism could provide an explanation for both former apparent eternity of communist leaderships and their sudden collapse.
---
paper_title: Majority rule, hierarchical structures, and democratic totalitarianism: a statistical approach

paper_content:

Abstract An alternative model to the formation of pyramidal structures is presented in the framework of social systems. The population is assumed to be distributed between two social orientations G and H with respective probabilities p 0 and (1 − p 0 ). Instead of starting the hierarchy with a given H -orientation at the top and then going downwards in a deterministic way, the hierarchy is initiated randomly at the bottom from the surrounding population. Every level is then selected from the one underneath using the principle of majority rule. The hierarchy is thus self-oriented at the top. It is shown how such self-oriented hierarchies are always H -oriented provided they have a minimal number of levels which is determined by the value of p 0 . Their stability is studied against increases in p 0 . An ideal transition to G -self-oriented hierarchies is obtained.
---
paper_title: Social paradoxes of majority rule voting and renormalization group

paper_content:

Real-space renormalization group ideas are used to study a voting problem in political science. A model to construct self-directed pyramidal structures from bottom up to the top is presented. Using majority rules, it is shown that a minority and even a majority can be systematically self-eliminated from top leadership, provided the hierarchy has a minimal number of levels. In some cases, 70% of the population is found to have zero representation after six hierarchical levels. Results are discussed with respect to the internal operation of political organizations.
---
paper_title: Real space renormalization group and totalitarian paradox of majority rule voting

paper_content:

The effect of majority rule voting in hierarchical structures is studied using the basic concepts from real space renormalization group. It shows in particular that a huge majority can be self-eliminated while climbing up the hierarchy levels. This majority democratic self-elimination articulates around the existence of fixed points in the voting flow. An unstable fixed point determines the critical threshold to full and total power. It can be varied from 50% up to 77% of initial support. Our model could shed new light on the last century eastern European communist collapse.
---
paper_title: Application of statistical physics to politics

paper_content:

The concept and technics of real space renormalization group are applied to study majority rule voting in hierarchical structures. It is found that democratic voting can lead to totalitarianism by keeping in power a small minority. Conditions of this paradox are analyzed and singled out. Indeed majority rule produces critical thresholds to absolute power. Values of these thresholds can vary from 50% up to at least 77%. The associated underlying mechanism could provide an explanation for both former apparent eternity of communist leaderships and their sudden collapse.
---
paper_title: Majority rule, hierarchical structures, and democratic totalitarianism: a statistical approach

paper_content:

Abstract An alternative model to the formation of pyramidal structures is presented in the framework of social systems. The population is assumed to be distributed between two social orientations G and H with respective probabilities p 0 and (1 − p 0 ). Instead of starting the hierarchy with a given H -orientation at the top and then going downwards in a deterministic way, the hierarchy is initiated randomly at the bottom from the surrounding population. Every level is then selected from the one underneath using the principle of majority rule. The hierarchy is thus self-oriented at the top. It is shown how such self-oriented hierarchies are always H -oriented provided they have a minimal number of levels which is determined by the value of p 0 . Their stability is studied against increases in p 0 . An ideal transition to G -self-oriented hierarchies is obtained.
---
paper_title: Stability of leadership in bottom-up hierarchical organizations

paper_content:

The stability of a leadership against a growing internal opposition is studied in bottom-up hierarchical organizations. Using a very simple model with bottom-up majority rule voting, the dynamics of power distribution at the various hierarchical levels is calculated within a probabilistic framework. Given a leadership at the top, the opposition weight from the hierarchy bottom is shown to fall off quickly while climbing up the hierarchy. It reaches zero after only a few hierarchical levels. Indeed the voting process is found to obey a threshold dynamics with a deterministic top outcome. Accordingly the leadership may stay stable against very large amplitude increases in the opposition at the bottom level. An opposition can thus grow steadily from few percent up to seventy seven percent with not one a single change at the elected top level. However and in contrast, from one election to another, in the vicinity of the threshold, less than a one percent additional shift at the bottom level can drive a drastic and brutal change at the top. The opposition topples the current leadership at once. In addition to analytical formulas, results from a large scale simulation are presented. The results may shed a new light on management architectures as well as on alert systems. They could also provide some
---
paper_title: Social paradoxes of majority rule voting and renormalization group

paper_content:

Real-space renormalization group ideas are used to study a voting problem in political science. A model to construct self-directed pyramidal structures from bottom up to the top is presented. Using majority rules, it is shown that a minority and even a majority can be systematically self-eliminated from top leadership, provided the hierarchy has a minimal number of levels. In some cases, 70% of the population is found to have zero representation after six hierarchical levels. Results are discussed with respect to the internal operation of political organizations.
---
paper_title: Real space renormalization group and totalitarian paradox of majority rule voting

paper_content:

The effect of majority rule voting in hierarchical structures is studied using the basic concepts from real space renormalization group. It shows in particular that a huge majority can be self-eliminated while climbing up the hierarchy levels. This majority democratic self-elimination articulates around the existence of fixed points in the voting flow. An unstable fixed point determines the critical threshold to full and total power. It can be varied from 50% up to 77% of initial support. Our model could shed new light on the last century eastern European communist collapse.
---
paper_title: Application of statistical physics to politics

paper_content:

The concept and technics of real space renormalization group are applied to study majority rule voting in hierarchical structures. It is found that democratic voting can lead to totalitarianism by keeping in power a small minority. Conditions of this paradox are analyzed and singled out. Indeed majority rule produces critical thresholds to absolute power. Values of these thresholds can vary from 50% up to at least 77%. The associated underlying mechanism could provide an explanation for both former apparent eternity of communist leaderships and their sudden collapse.
---
paper_title: Dictatorship from majority rule voting

paper_content:

Abstract:Majority rule voting in a multi-level system is studied using tools from the physics of disorder. We are not dealing with nation-wide general elections but rather with hierarchical organisations made of small committees. While in theory, for a two candidate election, the critical threshold to absolute power is , the usual existence of some local and reasonable bias makes it asymmetric, transforming a democratic system in effect to a dictatorship. The underlying dynamics of this democratic self-elimination is studied using a simulation which visualizes the full process. In addition the effect of non-voting persons (abstention, sickness, apathy) is also studied. It is found to have an additional drastic effect on the asymmetry of the threshold value to power. Some possible applications are mentioned.
---
paper_title: Real space renormalization group and totalitarian paradox of majority rule voting

paper_content:

The effect of majority rule voting in hierarchical structures is studied using the basic concepts from real space renormalization group. It shows in particular that a huge majority can be self-eliminated while climbing up the hierarchy levels. This majority democratic self-elimination articulates around the existence of fixed points in the voting flow. An unstable fixed point determines the critical threshold to full and total power. It can be varied from 50% up to 77% of initial support. Our model could shed new light on the last century eastern European communist collapse.
---
paper_title: Political paradoxes of majority rule voting and hierarchical systems

paper_content:

The use of majority rule voting is believed to be instrumental to establish democratic operating of political organizations. However in this work it is shown that, while applied to hierarchical systems, it leads to political paradoxes. To substantiate these findings a model to construct self-directed pyramidal structures from bottom up to the top is presented. Using majority rules it is shown that a minority and even a majority can be systematically self-eliminated from top leadership, provided the hierarchy has a minimal number of levels. In some cases, 70% of the population is found to have zero representation after 6 hierarchical levels. Results are discussed with respect to internal operating of political organizations.
---
paper_title: Towards a theory of collective phenomena: Consensus and attitude changes in groups

paper_content:

This study presents the outline of a model for collective phenomena. A symmetry-breaking model combines a number of well-established social psychology hypotheses with recent concepts of statistical physics. Specifically we start out from the regularities obtained in studies on the polarization of attitudes and decisions. From a strictly logical point of view, it is immediately clear that aggregation effects must be analysed separately from group effects as such. The conceptual analysis of the assumed mechanisms reveals that when we deal with phenomena that have until now been designated as polarization phenomena, we are faced not with a single phenomenon, as was believed hitherto, but with a whole class of phenomena. For this reason it would be appropriate to deal with them differentially both from an empirical and from a theoretical point of view. It is possible to show, moreover, that in principle polarization is a direct function of interaction and, beyond a critical threshold an inverse function of the differentiation between group members. A certain number of verifiable conjectures are presented on the basis of physio-mathematical-psychological considerations. It is to be hoped that these theoretical outlines will make it possible to give a new lease on life to a field of research that has established solid facts, but that became trapped in a dead-end road, for lack of a sufficiently broad analysis.
---
paper_title: Sociophysics: A mean behavior model for the process of strike

paper_content:

Plant for the treatment and the oxidation of antimony minerals, wherein an antimony mineral with any granulometry and humidity, eventually crushed, is carried by a hot gaseous stream, subjected to milling, drying, subsequent separations and then introduced in a rotary kiln in a state of extreme subdivision and oxidized dispersed in a gaseous compressed oxidizing stream.
---
paper_title: Sociophysics: A mean behavior model for the process of strike

paper_content:

Plant for the treatment and the oxidation of antimony minerals, wherein an antimony mineral with any granulometry and humidity, eventually crushed, is carried by a hot gaseous stream, subjected to milling, drying, subsequent separations and then introduced in a rotary kiln in a state of extreme subdivision and oxidized dispersed in a gaseous compressed oxidizing stream.
---
paper_title: Rational group decision making: a random field Ising model at

paper_content:

A modified version of a finite random field Ising ferromagnetic model in an external magnetic field at zero temperature is presented to describe group decision making. Fields may have a non-zero average. A postulate of minimum inter-individual conflicts is assumed. Interactions then produce a group polarization along one very choice which is however randomly selected. A small external social pressure is shown to have a drastic effect on the polarization. Individual bias related to personal backgrounds, cultural values and past experiences are introduced via quenched local competing fields. They are shown to be instrumental in generating a larger spectrum of collective new choices beyond initial ones. In particular, compromise is found to results from the existence of individual competing bias. Conflict is shown to weaken group polarization. The model yields new psychosociological insights about consensus and compromise in groups.
---
paper_title: Towards a theory of collective phenomena. III: Conflicts and forms of power

paper_content:

This paper further develops a new theory of power advanced by the authors in two previous papers (Galam and Moscovici, 1991, 1994). According to this theory power results from the build up of conflicts within a group, these conflicts requiring a degree of organizational complexity which is itself a decreasing function of group size. Within this approach, power appears to be a composite of three qualitatively different powers, institutional, generative and ecological. Levels and relationships among these forms of power are considered as a function of the diversity of the group. There exist also three states of organization associated with power evolution. At the group initial stage is the paradigmatic state. Creation and inclusion of conflicts are accomplished in the transitional state through the building of complexity. At a critical value of diversity, the group moves into the agonal state in which institutional power vanishes simultaneously with the fusion of generative and ecological powers
---
paper_title: Universality of Group Decision Making

paper_content:

Group decision making is assumed to obey some universal features which are independent of both the social nature of the group making the decision and the nature of the decision itself. On this basis a simple magnetic like model is built. Pair interactions are introduced to measure the degree of exchange among individuals while discussing. An external uniform field is included to account for a possible pressure from outside. Individual biases with respect to the issue at stake are also included using local random fields. A unique postulate of minimum conflict is assumed. The model is then solved with emphasize on its psycho-sociological implications. Counter-intuitive results are obtained. At this stage no new physical technicality is involved. Instead, the full psycho-sociological implications of the model are drawn. Few cases are then detailed to enlight them.
---
paper_title: From Individual Choice to Group Decision Making

paper_content:

Some universal features are independent of both the social nature of the individuals making the decision and the nature of the decision itself. On this basis a simple magnet like model is built. Pair interactions are introduced to measure the degree of exchange among individuals while discussing. An external uniform field is included to account for a possible pressure from outside. Individual biases with respect to the issue at stake are also included using local random fields. A unique postulate of minimum conflict is assumed. The model is then solved with emphasis on its psycho-sociological implications. Counter-intuitive results are obtained. At this stage no new physical technicality is involved. Instead the full psycho-sociological implications of the model are drawn. Few cases are then detailed to enlight them. In addition, several numerical experiments based on our model are shown to give both an insight on the dynamics of the model and suggest further research directions.
---
paper_title: Towards a theory of collective phenomena. II: Conformity and power

paper_content:

A new theory of power is presented using the concept of symmetry breakdown in small and large groups. Power appears to result from the building up of conflicts within the group. Introduction and support of these conflicts requires an internal organization of the group. The organization-associated complexity is a decreasing function of group size. Thus small groups have more difficulties in generating internal conflicts than large ones. This group dynamic is characterized by two states which are different in their nature. The group is first built within the paradigmatic state aimed to determine and reproduce group conformity The group challenge is then to reach the transitional state which enriches the group possibilities through the inclusion and stabilization of internal conflicts.
---
paper_title: Towards a theory of collective phenomena: Consensus and attitude changes in groups

paper_content:

This study presents the outline of a model for collective phenomena. A symmetry-breaking model combines a number of well-established social psychology hypotheses with recent concepts of statistical physics. Specifically we start out from the regularities obtained in studies on the polarization of attitudes and decisions. From a strictly logical point of view, it is immediately clear that aggregation effects must be analysed separately from group effects as such. The conceptual analysis of the assumed mechanisms reveals that when we deal with phenomena that have until now been designated as polarization phenomena, we are faced not with a single phenomenon, as was believed hitherto, but with a whole class of phenomena. For this reason it would be appropriate to deal with them differentially both from an empirical and from a theoretical point of view. It is possible to show, moreover, that in principle polarization is a direct function of interaction and, beyond a critical threshold an inverse function of the differentiation between group members. A certain number of verifiable conjectures are presented on the basis of physio-mathematical-psychological considerations. It is to be hoped that these theoretical outlines will make it possible to give a new lease on life to a field of research that has established solid facts, but that became trapped in a dead-end road, for lack of a sufficiently broad analysis.
---
paper_title: Sociophysics: A mean behavior model for the process of strike

paper_content:

Plant for the treatment and the oxidation of antimony minerals, wherein an antimony mineral with any granulometry and humidity, eventually crushed, is carried by a hot gaseous stream, subjected to milling, drying, subsequent separations and then introduced in a rotary kiln in a state of extreme subdivision and oxidized dispersed in a gaseous compressed oxidizing stream.
---
paper_title: Rational group decision making: a random field Ising model at

paper_content:

A modified version of a finite random field Ising ferromagnetic model in an external magnetic field at zero temperature is presented to describe group decision making. Fields may have a non-zero average. A postulate of minimum inter-individual conflicts is assumed. Interactions then produce a group polarization along one very choice which is however randomly selected. A small external social pressure is shown to have a drastic effect on the polarization. Individual bias related to personal backgrounds, cultural values and past experiences are introduced via quenched local competing fields. They are shown to be instrumental in generating a larger spectrum of collective new choices beyond initial ones. In particular, compromise is found to results from the existence of individual competing bias. Conflict is shown to weaken group polarization. The model yields new psychosociological insights about consensus and compromise in groups.
---
paper_title: Towards a theory of collective phenomena. III: Conflicts and forms of power

paper_content:

This paper further develops a new theory of power advanced by the authors in two previous papers (Galam and Moscovici, 1991, 1994). According to this theory power results from the build up of conflicts within a group, these conflicts requiring a degree of organizational complexity which is itself a decreasing function of group size. Within this approach, power appears to be a composite of three qualitatively different powers, institutional, generative and ecological. Levels and relationships among these forms of power are considered as a function of the diversity of the group. There exist also three states of organization associated with power evolution. At the group initial stage is the paradigmatic state. Creation and inclusion of conflicts are accomplished in the transitional state through the building of complexity. At a critical value of diversity, the group moves into the agonal state in which institutional power vanishes simultaneously with the fusion of generative and ecological powers
---
paper_title: Universality of Group Decision Making

paper_content:

Group decision making is assumed to obey some universal features which are independent of both the social nature of the group making the decision and the nature of the decision itself. On this basis a simple magnetic like model is built. Pair interactions are introduced to measure the degree of exchange among individuals while discussing. An external uniform field is included to account for a possible pressure from outside. Individual biases with respect to the issue at stake are also included using local random fields. A unique postulate of minimum conflict is assumed. The model is then solved with emphasize on its psycho-sociological implications. Counter-intuitive results are obtained. At this stage no new physical technicality is involved. Instead, the full psycho-sociological implications of the model are drawn. Few cases are then detailed to enlight them.
---
paper_title: From Individual Choice to Group Decision Making

paper_content:

Some universal features are independent of both the social nature of the individuals making the decision and the nature of the decision itself. On this basis a simple magnet like model is built. Pair interactions are introduced to measure the degree of exchange among individuals while discussing. An external uniform field is included to account for a possible pressure from outside. Individual biases with respect to the issue at stake are also included using local random fields. A unique postulate of minimum conflict is assumed. The model is then solved with emphasis on its psycho-sociological implications. Counter-intuitive results are obtained. At this stage no new physical technicality is involved. Instead the full psycho-sociological implications of the model are drawn. Few cases are then detailed to enlight them. In addition, several numerical experiments based on our model are shown to give both an insight on the dynamics of the model and suggest further research directions.
---
paper_title: Towards a theory of collective phenomena. II: Conformity and power

paper_content:

A new theory of power is presented using the concept of symmetry breakdown in small and large groups. Power appears to result from the building up of conflicts within the group. Introduction and support of these conflicts requires an internal organization of the group. The organization-associated complexity is a decreasing function of group size. Thus small groups have more difficulties in generating internal conflicts than large ones. This group dynamic is characterized by two states which are different in their nature. The group is first built within the paradigmatic state aimed to determine and reproduce group conformity The group challenge is then to reach the transitional state which enriches the group possibilities through the inclusion and stabilization of internal conflicts.
---
paper_title: Towards a theory of collective phenomena: Consensus and attitude changes in groups

paper_content:

This study presents the outline of a model for collective phenomena. A symmetry-breaking model combines a number of well-established social psychology hypotheses with recent concepts of statistical physics. Specifically we start out from the regularities obtained in studies on the polarization of attitudes and decisions. From a strictly logical point of view, it is immediately clear that aggregation effects must be analysed separately from group effects as such. The conceptual analysis of the assumed mechanisms reveals that when we deal with phenomena that have until now been designated as polarization phenomena, we are faced not with a single phenomenon, as was believed hitherto, but with a whole class of phenomena. For this reason it would be appropriate to deal with them differentially both from an empirical and from a theoretical point of view. It is possible to show, moreover, that in principle polarization is a direct function of interaction and, beyond a critical threshold an inverse function of the differentiation between group members. A certain number of verifiable conjectures are presented on the basis of physio-mathematical-psychological considerations. It is to be hoped that these theoretical outlines will make it possible to give a new lease on life to a field of research that has established solid facts, but that became trapped in a dead-end road, for lack of a sufficiently broad analysis.
---
paper_title: Spontaneous Coalition Forming. Why Some Are Stable?

paper_content:

A model to describe the spontaneous formation of military and economic coalitions among a group of countries is proposed using spin glass theory. Between each couple of countries, there exists a bond exchange coupling which is either zero, cooperative or conflicting. It depends on their common history, specific nature, and cannot be varied. Then, given a frozen random bond distribution, coalitions are found to spontaneously form. However they are also unstable making the system very disordered. Countries shift coalitions all the time. Only the setting of macro extra national coalition are shown to stabilize alliances among countries. The model gives new light on the recent instabilities produced in Eastern Europe by the Warsow pact dissolution at odd to the previous communist stability. Current European stability is also discussed with respect to the European Union construction.
---
paper_title: Fragmentation versus stability in bimodal coalitions

paper_content:

Competing bimodal coalitions among a group of actors are discussed. First, a model from political sciences is revisited. Most of the model statements are found not to be contained in the model. Second, a new coalition model is built. It accounts for local versus global alignment with respect to the joining of a coalition. The existence of two competing world coaltions is found to yield one unique stable distribution of actors. On the opposite a unique world leadership allows the emergence of unstable relationships. In parallel to regular actors which have a clear coalition choice, ``neutral"``frustrated"and ``risky"actors are produced. The cold war organisation after world war II is shown to be rather stable. The emergence of a fragmentation process from eastern group disappearance is explained as well as continuing western group stability. Some hints are obtained about possible policies to stabilize world nation relationships. European construction is analyzed with respect to european stability. Chinese stability is also discussed.
---
paper_title: Comment on “A landscape theory of aggregation”

paper_content:

The problem of aggregation processes in alignments is the subject of a paper published recently in a statistical physics journal. Two models are presented and discussed in that paper. First, the energy landscape model proposed by Robert Axelrod and D. Scott Bennett (this Journal, 23 (1993), 211–33) is analysed. The model is shown not to include most of its claimed results. Then a second model is presented to reformulate the problem correctly within statistical physics and to extend it beyond the initial Axelrod-Bennett analogy. ::: Serge Galam, ‘Fragmentation Versus Stability in Bimodal Coalitions’, Physica A , 230 (1966), 174–88.
---
paper_title: Optimizing Conflicts in the Formation of Strategic Alliances

paper_content:

Abstract:Coalition setting among a set of actors (countries, firms, individuals) is studied using concepts from the theory of spin glasses. Given the distribution of respective bilateral propensities to either cooperation or conflict, the phenomenon of local aggregation is modeled. In particular the number of coalitions is determined according to a minimum conflict principle. It is found not to be always two. Along these lines, previous studies are revisited and are found not to be consistent with their own principles. The model is then used to describe the fragmentation of former Yugoslavia. Results are compared to the actual situation.
---
paper_title: Spontaneous Coalition Forming. Why Some Are Stable?

paper_content:

A model to describe the spontaneous formation of military and economic coalitions among a group of countries is proposed using spin glass theory. Between each couple of countries, there exists a bond exchange coupling which is either zero, cooperative or conflicting. It depends on their common history, specific nature, and cannot be varied. Then, given a frozen random bond distribution, coalitions are found to spontaneously form. However they are also unstable making the system very disordered. Countries shift coalitions all the time. Only the setting of macro extra national coalition are shown to stabilize alliances among countries. The model gives new light on the recent instabilities produced in Eastern Europe by the Warsow pact dissolution at odd to the previous communist stability. Current European stability is also discussed with respect to the European Union construction.
---
paper_title: Fragmentation versus stability in bimodal coalitions

paper_content:

Competing bimodal coalitions among a group of actors are discussed. First, a model from political sciences is revisited. Most of the model statements are found not to be contained in the model. Second, a new coalition model is built. It accounts for local versus global alignment with respect to the joining of a coalition. The existence of two competing world coaltions is found to yield one unique stable distribution of actors. On the opposite a unique world leadership allows the emergence of unstable relationships. In parallel to regular actors which have a clear coalition choice, ``neutral"``frustrated"and ``risky"actors are produced. The cold war organisation after world war II is shown to be rather stable. The emergence of a fragmentation process from eastern group disappearance is explained as well as continuing western group stability. Some hints are obtained about possible policies to stabilize world nation relationships. European construction is analyzed with respect to european stability. Chinese stability is also discussed.
---
paper_title: Comment on “A landscape theory of aggregation”

paper_content:

The problem of aggregation processes in alignments is the subject of a paper published recently in a statistical physics journal. Two models are presented and discussed in that paper. First, the energy landscape model proposed by Robert Axelrod and D. Scott Bennett (this Journal, 23 (1993), 211–33) is analysed. The model is shown not to include most of its claimed results. Then a second model is presented to reformulate the problem correctly within statistical physics and to extend it beyond the initial Axelrod-Bennett analogy. ::: Serge Galam, ‘Fragmentation Versus Stability in Bimodal Coalitions’, Physica A , 230 (1966), 174–88.
---
paper_title: Spontaneous Coalition Forming. Why Some Are Stable?

paper_content:

A model to describe the spontaneous formation of military and economic coalitions among a group of countries is proposed using spin glass theory. Between each couple of countries, there exists a bond exchange coupling which is either zero, cooperative or conflicting. It depends on their common history, specific nature, and cannot be varied. Then, given a frozen random bond distribution, coalitions are found to spontaneously form. However they are also unstable making the system very disordered. Countries shift coalitions all the time. Only the setting of macro extra national coalition are shown to stabilize alliances among countries. The model gives new light on the recent instabilities produced in Eastern Europe by the Warsow pact dissolution at odd to the previous communist stability. Current European stability is also discussed with respect to the European Union construction.
---
paper_title: Fragmentation versus stability in bimodal coalitions

paper_content:

Competing bimodal coalitions among a group of actors are discussed. First, a model from political sciences is revisited. Most of the model statements are found not to be contained in the model. Second, a new coalition model is built. It accounts for local versus global alignment with respect to the joining of a coalition. The existence of two competing world coaltions is found to yield one unique stable distribution of actors. On the opposite a unique world leadership allows the emergence of unstable relationships. In parallel to regular actors which have a clear coalition choice, ``neutral"``frustrated"and ``risky"actors are produced. The cold war organisation after world war II is shown to be rather stable. The emergence of a fragmentation process from eastern group disappearance is explained as well as continuing western group stability. Some hints are obtained about possible policies to stabilize world nation relationships. European construction is analyzed with respect to european stability. Chinese stability is also discussed.
---
paper_title: Comment on “A landscape theory of aggregation”

paper_content:

The problem of aggregation processes in alignments is the subject of a paper published recently in a statistical physics journal. Two models are presented and discussed in that paper. First, the energy landscape model proposed by Robert Axelrod and D. Scott Bennett (this Journal, 23 (1993), 211–33) is analysed. The model is shown not to include most of its claimed results. Then a second model is presented to reformulate the problem correctly within statistical physics and to extend it beyond the initial Axelrod-Bennett analogy. ::: Serge Galam, ‘Fragmentation Versus Stability in Bimodal Coalitions’, Physica A , 230 (1966), 174–88.
---
paper_title: Majority rule, hierarchical structures, and democratic totalitarianism: a statistical approach

paper_content:

Abstract An alternative model to the formation of pyramidal structures is presented in the framework of social systems. The population is assumed to be distributed between two social orientations G and H with respective probabilities p 0 and (1 − p 0 ). Instead of starting the hierarchy with a given H -orientation at the top and then going downwards in a deterministic way, the hierarchy is initiated randomly at the bottom from the surrounding population. Every level is then selected from the one underneath using the principle of majority rule. The hierarchy is thus self-oriented at the top. It is shown how such self-oriented hierarchies are always H -oriented provided they have a minimal number of levels which is determined by the value of p 0 . Their stability is studied against increases in p 0 . An ideal transition to G -self-oriented hierarchies is obtained.
---
paper_title: Optimizing Conflicts in the Formation of Strategic Alliances

paper_content:

Abstract:Coalition setting among a set of actors (countries, firms, individuals) is studied using concepts from the theory of spin glasses. Given the distribution of respective bilateral propensities to either cooperation or conflict, the phenomenon of local aggregation is modeled. In particular the number of coalitions is determined according to a minimum conflict principle. It is found not to be always two. Along these lines, previous studies are revisited and are found not to be consistent with their own principles. The model is then used to describe the fragmentation of former Yugoslavia. Results are compared to the actual situation.
---
paper_title: Spontaneous Coalition Forming. Why Some Are Stable?

paper_content:

A model to describe the spontaneous formation of military and economic coalitions among a group of countries is proposed using spin glass theory. Between each couple of countries, there exists a bond exchange coupling which is either zero, cooperative or conflicting. It depends on their common history, specific nature, and cannot be varied. Then, given a frozen random bond distribution, coalitions are found to spontaneously form. However they are also unstable making the system very disordered. Countries shift coalitions all the time. Only the setting of macro extra national coalition are shown to stabilize alliances among countries. The model gives new light on the recent instabilities produced in Eastern Europe by the Warsow pact dissolution at odd to the previous communist stability. Current European stability is also discussed with respect to the European Union construction.
---
paper_title: Fragmentation versus stability in bimodal coalitions

paper_content:

Competing bimodal coalitions among a group of actors are discussed. First, a model from political sciences is revisited. Most of the model statements are found not to be contained in the model. Second, a new coalition model is built. It accounts for local versus global alignment with respect to the joining of a coalition. The existence of two competing world coaltions is found to yield one unique stable distribution of actors. On the opposite a unique world leadership allows the emergence of unstable relationships. In parallel to regular actors which have a clear coalition choice, ``neutral"``frustrated"and ``risky"actors are produced. The cold war organisation after world war II is shown to be rather stable. The emergence of a fragmentation process from eastern group disappearance is explained as well as continuing western group stability. Some hints are obtained about possible policies to stabilize world nation relationships. European construction is analyzed with respect to european stability. Chinese stability is also discussed.
---
paper_title: Comment on “A landscape theory of aggregation”

paper_content:

The problem of aggregation processes in alignments is the subject of a paper published recently in a statistical physics journal. Two models are presented and discussed in that paper. First, the energy landscape model proposed by Robert Axelrod and D. Scott Bennett (this Journal, 23 (1993), 211–33) is analysed. The model is shown not to include most of its claimed results. Then a second model is presented to reformulate the problem correctly within statistical physics and to extend it beyond the initial Axelrod-Bennett analogy. ::: Serge Galam, ‘Fragmentation Versus Stability in Bimodal Coalitions’, Physica A , 230 (1966), 174–88.
---
paper_title: Optimizing Conflicts in the Formation of Strategic Alliances

paper_content:

Abstract:Coalition setting among a set of actors (countries, firms, individuals) is studied using concepts from the theory of spin glasses. Given the distribution of respective bilateral propensities to either cooperation or conflict, the phenomenon of local aggregation is modeled. In particular the number of coalitions is determined according to a minimum conflict principle. It is found not to be always two. Along these lines, previous studies are revisited and are found not to be consistent with their own principles. The model is then used to describe the fragmentation of former Yugoslavia. Results are compared to the actual situation.
---
paper_title: On reducing terrorism power: a hint from physics

paper_content:

The September 11 attack on the US has revealed an unprecedented terrorism worldwide range of destruction. Recently, it has been related to the percolation of worldwide spread passive supporters. This scheme puts the suppression of the percolation effect as the major strategic issue in the fight against terrorism. Accordingly the world density of passive supporters should be reduced below the percolation threshold. In terms of solid policy, it means to neutralize millions of random passive supporters, which is contrary to ethics and out of any sound practical scheme. Given this impossibility we suggest instead a new strategic scheme to act directly on the value of the terrorism percolation threshold itself without harming the passive supporters. Accordingly we identify the space hosting the percolation phenomenon to be a multi-dimensional virtual social space which extends the ground earth surface to include the various independent terrorist-fighting goals. The associated percolating cluster is then found to create long-range ground connections to terrorism activity. We are thus able to modify the percolation threshold pc in the virtual space to reach p<pc by decreasing the social space dimension, leaving the density p unchanged. At once that would break down the associated world terrorism network to a family of unconnected finite-size clusters. The current world terrorism threat would thus shrink immediately and spontaneously to a local geographic problem. There, military action would become limited and efficient.
---
paper_title: Global Physics: From Percolation to Terrorism, Guerilla Warfare and Clandestine Activities

paper_content:

The September 11 attack on the US has revealed an unprecedented terrorism with worldwide range of destruction. It is argued to result from the first worldwide percolation of passive supporters. They are people sympathetic to the terrorism cause but without being involved with it. They just do not oppose it in case they could. This scheme puts suppression of the percolation as the major strategic issue in the fight against terrorism. Acting on the population is shown to be useless. Instead a new strategic scheme is suggested to increase the terrorism percolation threshold and in turn suppress the percolation. The relevant associated space is identified as a multi-dimensional social space including both the ground earth surface and all various independent flags displayed by the terrorist group. Some hints are given on how to shrink the geographical spreading of terrorism threat. The model apply to a large spectrum of clandestine activities including guerilla warfare as well as tax evasion, corruption, illegal gambling, illegal prostitution and black markets.
---
paper_title: Local dynamics vs.?social mechanisms: A unifying frame

paper_content:

We present a general sequential probabilistic frame, which extends a series of earlier opinion dynamics models. In addition, it orders and classifies all of the existing two-state spin systems. The scheme operates via local updates where a majority rule is applied differently in each possible configuration of a local group. It is weighted by a local probability which is a function of the local value of the order parameter, i.e., the majority-to-minority ratio. The system is thus driven from one equilibrium state into another equilibrium state till no collective change occurs. A phase diagram can thus be constructed. It has two phases, one where the collective opinion ends up broken along one opinion, and another with an even coexistence of both opinions. Two different regimes, monotonic and dampened oscillatory, are found for the coexistence phase. At the phase transition local probabilities conserve the density of opinions and reproduce the collective dynamics of the Voter model. The essential behavior of all existing discrete two-state models (Galam, Sznajd, Ochrombel, Stauffer, Krapivsky-Redner, Mobilia-Redner, Behera-Schweitzer, Slanina-Lavicka, Sanchez ...) is recovered and found to depart from each other only in the value of their local probabilities. Corresponding simulations are discussed. It is concluded that one should not judge from the above model results the validity of their respective psycho-social assumptions.
---
paper_title: From 2000 Bush-Gore to 2006 Italian elections: Voting at fifty-fifty and the Contrarian Effect

paper_content:

A sociophysical model for opinion dynamics is shown to embody a series of recent western hung national votes all set at the unexpected and very improbable edge of a fifty-fifty score. It started with the Bush–Gore 2000 American presidential election, followed by the 2002 Stoiber–Schroder, then the 2005 Schroder–Merkel German elections, and finally the 2006 Prodi-Berlusconi Italian elections. In each case, the country was facing drastic choices, the running competing parties were advocating very different programs and millions of voters were involved. Moreover, polls were given a substantial margin for the predicted winner. While all these events were perceived as accidental and isolated, our model suggests that indeed they are deterministic and obey to one single universal phenomena associated to the effect of contrarian behavior on the dynamics of opinion forming. The not hung Bush–Kerry 2004 presidential election is shown to belong to the same universal frame. To conclude, the existence of contrarians hints at the repetition of hung elections in the near future.
---
paper_title: Modeling rumors: The no plane pentagon french hoax case

paper_content:

The recent astonishing wide adhesion of French people to the rumor claiming ‘No plane did crash on the Pentagon on September 11’, is given a generic explanation in terms of a model of minority opinion spreading. Using a majority rule reaction–diffusion dynamics, a rumor is shown to invade for sure a social group provided it fulfills simultaneously two criteria. First it must initiate with a support beyond some critical threshold which however, turns out to be always very low. Then it has to be consistent with some larger collective social paradigm of the group. Otherwise it just dies out. Both conditions were satisfied in the French case with the associated book sold at more than 200 000 copies in just a few days. The rumor was stopped by the firm stand of most newspaper editors stating it is nonsense. Such an incredible social dynamics is shown to result naturally from an open and free public debate among friends and colleagues. Each one searching for the truth sincerely on a free will basis and without individual biases. The polarization process appears also to be very quick in agreement with reality. It is a very strong anti-democratic reversal of opinion although made quite democratically. The model may apply to a large range of rumors.
---
paper_title: Opinion dynamics in a three-choice system

paper_content:

We generalize Galam’s model of opinion spreading by introducing three competing choices. At each update, the population is randomly divided in groups of three agents, whose members adopt the opinion of the local majority. In the case of a tie, the local group adopts opinion A, B or C with probabilities α, β and (1-α-β) respectively. We derive the associated phase diagrams and dynamics by both analytical means and simulations. Polarization is always reached within very short time scales. We point out situations in which an initially very small minority opinion can invade the whole system.
---
paper_title: An evolution theory in finite size systems

paper_content:

A new model of evolution is presented for finite size systems. Conditions under which a minority species can emerge, spread and stabilize to a macroscopic size are studied. It is found that space organization is instrumental in addition to a qualitative advantage. Some peculiar topologies ensure the overcome of the initial majority species. However the probability of such local clusters is very small and depend strongly on the system size. A probabilistic phase diagram is obtained for small sizes. It reduces to a trivial situation in the thermodynamic limit, thus indicating the importance of dealing with finite systems in evolution problems. Results are discussed with respect to both Darwin and punctuated equilibria theories.
---
paper_title: Killer Geometries in Competing Species Dynamics

paper_content:

We discuss a cellular automata model to study the competition between an emergent better fitted species against an existing majority species. The model implements local fights among small group of individuals and a synchronous random walk on a 2D lattice. The faith of the system, i.e., the spreading or disappearance of the species is determined by their initial density and fight frequency. The initial density of the emergent species has to be higher than a critical threshold for total spreading but this value depends in a non-trivial way on the fight frequency. Below the threshold any better adapted species disappears showing that a qualitative advantage is not enough for a minority to win. No strategy is involved but spatial organization turns out to be crucial. For instance, at minority densities of zero measure some very rare local geometries which occur by chance are found to be killer geometries. Once set they lead with high probability to the total destruction of the preexisting majority species. The occurrence rate of these killer geometries is a function of the system size. This model may apply to a large spectrum of competing groups like smoker–non smoker, opinion forming, diffusion of innovation setting of industrial standards, species evolution, epidemic spreading and cancer growth.
---
paper_title: The role of inflexible minorities in the breaking of democratic opinion dynamics

paper_content:

We study the effect of inflexible agents on two state opinion dynamics. The model operates via repeated local updates of random grouping of agents. While floater agents do eventually flip their opinion to follow the local majority, inflexible agents keep their opinion always unchanged. It is a quenched individual opinion. In the bare model (no inflexibles), a separator at 50% drives the dynamics towards either one of two pure attractors, each associated with a full polarization along one of the opinions. The initial majority wins. The existence of inflexibles for only one of the two opinions is found to shift the separator at a lower value than 50% in favor of that side. Moreover it creates an incompressible minority around the inflexibles, one of the pure attractors becoming a mixed phase attractor. In addition above a threshold of 17% inflexibles make their side sure of winning whatever the initial conditions are. The inflexible minority wins. An equal presence of inflexibles on both sides restores the balanced dynamics with again a separator at 50% and now two mixed phase attractors on each side. Nevertheless, beyond 25% the dynamics is reversed with a unique attractor at a 50–50 stable equilibrium. But a very small advantage in inflexibles results in a decisive lowering of the separator at the advantage of the corresponding opinion. A few percent advantage does guarantee to become majority with one single attractor. The model is solved exhaustedly for groups of size 3.
---
paper_title: FASHION, NOVELTY AND OPTIMALITY: An application from Physics

paper_content:

We apply a physical-based model to describe the clothes fashion market. Every time a new outlet appears on the market, it can invade the market under certain specific conditions. Hence, the “old” outlet can be completely dominated and disappears. Each creator competes for a finite population of agents. Fashion phenomena are shown to result from a collective phenomenon produced by local individual imitation effects. We assume that, in each step of the imitation process, agents only interact with a subset rather than with the whole set of agents. People are actually more likely to influence (and be influenced by) their close “neighbors”. Accordingly, we discuss which strategy is best fitted for new producers when people are either simply organized into anonymous reference groups or when they are organized in social groups hierarchically ordered. While counterfeits are shown to reinforce the first strategy, creating social leaders can permit to avoid them.
---
paper_title: Threshold Phenomena versus Killer Clusters in Bimodal Competion for Standards

paper_content:

Given an individually used standard on a territory we study the conditions for total spreading of a new emergent better fitted competing standard. The associated dynamics is monitored by local competing updating which occurs at random among a few individuals. The analysis is done using a cellular automata model within a two-dimensional lattice with synchronous random walk. Starting from an initial density of the new standard the associated density evolution is studied using groups of four individuals each. For each local update the outcome goes along the local majority within the group. However in case of a tie, the better fitted standard wins. Updates may happen at each diffusive step according to some fixed probability. For every value of that probability a critical threshold, in the initial new emergent standard density, is found to determine its total either disappearance or spreading making the process a threshold phenomenon. Nevertheless it turns out that even at a zero density measure of the new emergent standard there exits some peculiar killer clusters of it which have a non zero probability to grow and invade the whole system. At the same time the occurrence of such killer clusters is a very rare event and is a function of the system size. Application of the model to a large spectrum of competing dynamics is discussed. It includes the smoker-non smoker fight, opinion forming, diffusion of innovation, species evolution, epidemic spreading and cancer growth.
---
paper_title: Cancerous tumor: the high frequency of a rare event.

paper_content:

A simple model for cancer growth is presented using cellular automata. Cells diffuse randomly on a two-dimensional square lattice. Individual cells can turn cancerous at a very low rate. During each diffusive step, local fights may occur between healthy and cancerous cells. Associated outcomes depend on some biased local rules, which are independent of the overall cancerous cell density. The models unique ingredients are the frequency of local fights and the bias amplitude. While each isolated cancerous cell is eventually destroyed, an initial two-cell tumor cluster is found to have a nonzero probabilty to spread over the whole system. The associated phase diagram for survival or death is obtained as a function of both the rate of fight and the bias distribution. Within the model, although the occurrence of a killing cluster is a very rare event, it turns out to happen almost systematically over long periods of time, e.g., on the order of an adults life span. Thus, after some age, survival from tumorous cancer becomes random.
---
paper_title: An evolution theory in finite size systems

paper_content:

A new model of evolution is presented for finite size systems. Conditions under which a minority species can emerge, spread and stabilize to a macroscopic size are studied. It is found that space organization is instrumental in addition to a qualitative advantage. Some peculiar topologies ensure the overcome of the initial majority species. However the probability of such local clusters is very small and depend strongly on the system size. A probabilistic phase diagram is obtained for small sizes. It reduces to a trivial situation in the thermodynamic limit, thus indicating the importance of dealing with finite systems in evolution problems. Results are discussed with respect to both Darwin and punctuated equilibria theories.
---
paper_title: Killer Geometries in Competing Species Dynamics

paper_content:

We discuss a cellular automata model to study the competition between an emergent better fitted species against an existing majority species. The model implements local fights among small group of individuals and a synchronous random walk on a 2D lattice. The faith of the system, i.e., the spreading or disappearance of the species is determined by their initial density and fight frequency. The initial density of the emergent species has to be higher than a critical threshold for total spreading but this value depends in a non-trivial way on the fight frequency. Below the threshold any better adapted species disappears showing that a qualitative advantage is not enough for a minority to win. No strategy is involved but spatial organization turns out to be crucial. For instance, at minority densities of zero measure some very rare local geometries which occur by chance are found to be killer geometries. Once set they lead with high probability to the total destruction of the preexisting majority species. The occurrence rate of these killer geometries is a function of the system size. This model may apply to a large spectrum of competing groups like smoker–non smoker, opinion forming, diffusion of innovation setting of industrial standards, species evolution, epidemic spreading and cancer growth.
---
paper_title: From 2000 Bush-Gore to 2006 Italian elections: Voting at fifty-fifty and the Contrarian Effect

paper_content:

A sociophysical model for opinion dynamics is shown to embody a series of recent western hung national votes all set at the unexpected and very improbable edge of a fifty-fifty score. It started with the Bush–Gore 2000 American presidential election, followed by the 2002 Stoiber–Schroder, then the 2005 Schroder–Merkel German elections, and finally the 2006 Prodi-Berlusconi Italian elections. In each case, the country was facing drastic choices, the running competing parties were advocating very different programs and millions of voters were involved. Moreover, polls were given a substantial margin for the predicted winner. While all these events were perceived as accidental and isolated, our model suggests that indeed they are deterministic and obey to one single universal phenomena associated to the effect of contrarian behavior on the dynamics of opinion forming. The not hung Bush–Kerry 2004 presidential election is shown to belong to the same universal frame. To conclude, the existence of contrarians hints at the repetition of hung elections in the near future.
---
paper_title: Opinion dynamics in a three-choice system

paper_content:

We generalize Galam’s model of opinion spreading by introducing three competing choices. At each update, the population is randomly divided in groups of three agents, whose members adopt the opinion of the local majority. In the case of a tie, the local group adopts opinion A, B or C with probabilities α, β and (1-α-β) respectively. We derive the associated phase diagrams and dynamics by both analytical means and simulations. Polarization is always reached within very short time scales. We point out situations in which an initially very small minority opinion can invade the whole system.
---
paper_title: COEXISTENCE OF OPPOSITE GLOBAL SOCIAL FEELINGS: THE CASE OF PERCOLATION DRIVEN INSECURITY

paper_content:

A model of the dynamics of appearance of a new collective feeling, in addition and opposite to an existing one, is presented. Using percolation theory, the collective feeling of insecurity is shown to be able to coexist with the opposite collective feeling of safety. Indeed this coexistence of contradictory social feelings result from the simultaneous percolation of two infinite clusters of people who are respectively experiencing a safe and unsafe local environment. Therefore opposing claims on national debates over insecurity are shown to be possibly both valid.
---
paper_title: The role of inflexible minorities in the breaking of democratic opinion dynamics

paper_content:

We study the effect of inflexible agents on two state opinion dynamics. The model operates via repeated local updates of random grouping of agents. While floater agents do eventually flip their opinion to follow the local majority, inflexible agents keep their opinion always unchanged. It is a quenched individual opinion. In the bare model (no inflexibles), a separator at 50% drives the dynamics towards either one of two pure attractors, each associated with a full polarization along one of the opinions. The initial majority wins. The existence of inflexibles for only one of the two opinions is found to shift the separator at a lower value than 50% in favor of that side. Moreover it creates an incompressible minority around the inflexibles, one of the pure attractors becoming a mixed phase attractor. In addition above a threshold of 17% inflexibles make their side sure of winning whatever the initial conditions are. The inflexible minority wins. An equal presence of inflexibles on both sides restores the balanced dynamics with again a separator at 50% and now two mixed phase attractors on each side. Nevertheless, beyond 25% the dynamics is reversed with a unique attractor at a 50–50 stable equilibrium. But a very small advantage in inflexibles results in a decisive lowering of the separator at the advantage of the corresponding opinion. A few percent advantage does guarantee to become majority with one single attractor. The model is solved exhaustedly for groups of size 3.
---
paper_title: Local dynamics vs.?social mechanisms: A unifying frame

paper_content:

We present a general sequential probabilistic frame, which extends a series of earlier opinion dynamics models. In addition, it orders and classifies all of the existing two-state spin systems. The scheme operates via local updates where a majority rule is applied differently in each possible configuration of a local group. It is weighted by a local probability which is a function of the local value of the order parameter, i.e., the majority-to-minority ratio. The system is thus driven from one equilibrium state into another equilibrium state till no collective change occurs. A phase diagram can thus be constructed. It has two phases, one where the collective opinion ends up broken along one opinion, and another with an even coexistence of both opinions. Two different regimes, monotonic and dampened oscillatory, are found for the coexistence phase. At the phase transition local probabilities conserve the density of opinions and reproduce the collective dynamics of the Voter model. The essential behavior of all existing discrete two-state models (Galam, Sznajd, Ochrombel, Stauffer, Krapivsky-Redner, Mobilia-Redner, Behera-Schweitzer, Slanina-Lavicka, Sanchez ...) is recovered and found to depart from each other only in the value of their local probabilities. Corresponding simulations are discussed. It is concluded that one should not judge from the above model results the validity of their respective psycho-social assumptions.
---
paper_title: Modeling rumors: The no plane pentagon french hoax case

paper_content:

The recent astonishing wide adhesion of French people to the rumor claiming ‘No plane did crash on the Pentagon on September 11’, is given a generic explanation in terms of a model of minority opinion spreading. Using a majority rule reaction–diffusion dynamics, a rumor is shown to invade for sure a social group provided it fulfills simultaneously two criteria. First it must initiate with a support beyond some critical threshold which however, turns out to be always very low. Then it has to be consistent with some larger collective social paradigm of the group. Otherwise it just dies out. Both conditions were satisfied in the French case with the associated book sold at more than 200 000 copies in just a few days. The rumor was stopped by the firm stand of most newspaper editors stating it is nonsense. Such an incredible social dynamics is shown to result naturally from an open and free public debate among friends and colleagues. Each one searching for the truth sincerely on a free will basis and without individual biases. The polarization process appears also to be very quick in agreement with reality. It is a very strong anti-democratic reversal of opinion although made quite democratically. The model may apply to a large range of rumors.
---
paper_title: FASHION, NOVELTY AND OPTIMALITY: An application from Physics

paper_content:

We apply a physical-based model to describe the clothes fashion market. Every time a new outlet appears on the market, it can invade the market under certain specific conditions. Hence, the “old” outlet can be completely dominated and disappears. Each creator competes for a finite population of agents. Fashion phenomena are shown to result from a collective phenomenon produced by local individual imitation effects. We assume that, in each step of the imitation process, agents only interact with a subset rather than with the whole set of agents. People are actually more likely to influence (and be influenced by) their close “neighbors”. Accordingly, we discuss which strategy is best fitted for new producers when people are either simply organized into anonymous reference groups or when they are organized in social groups hierarchically ordered. While counterfeits are shown to reinforce the first strategy, creating social leaders can permit to avoid them.
---
paper_title: Sociophysics: a personal testimony

paper_content:

The origins of Sociophysics are discussed from a personal testimony. I trace back its history to the late 1970s. My 20 years of activities and research to establish and promote the field are reviewed. In particular, the conflicting nature of Sociophysics with the physics community is revealed from my own experience. Recent presentations of a supposed natural growth from Social Sciences are criticized.
---
paper_title: Local dynamics vs.?social mechanisms: A unifying frame

paper_content:

We present a general sequential probabilistic frame, which extends a series of earlier opinion dynamics models. In addition, it orders and classifies all of the existing two-state spin systems. The scheme operates via local updates where a majority rule is applied differently in each possible configuration of a local group. It is weighted by a local probability which is a function of the local value of the order parameter, i.e., the majority-to-minority ratio. The system is thus driven from one equilibrium state into another equilibrium state till no collective change occurs. A phase diagram can thus be constructed. It has two phases, one where the collective opinion ends up broken along one opinion, and another with an even coexistence of both opinions. Two different regimes, monotonic and dampened oscillatory, are found for the coexistence phase. At the phase transition local probabilities conserve the density of opinions and reproduce the collective dynamics of the Voter model. The essential behavior of all existing discrete two-state models (Galam, Sznajd, Ochrombel, Stauffer, Krapivsky-Redner, Mobilia-Redner, Behera-Schweitzer, Slanina-Lavicka, Sanchez ...) is recovered and found to depart from each other only in the value of their local probabilities. Corresponding simulations are discussed. It is concluded that one should not judge from the above model results the validity of their respective psycho-social assumptions.
---

Title: Sociophysics: A review of Galam models

Section 1: INTRODUCTION
Description 1: Introduce the field of sociophysics, tracing its emergence, development, and recognition within the physics community. Provide an overview of the key topics addressed in sociophysics, with an emphasis on opinion dynamics. Explain the scope and focus of this review, specifically on Galam models over the past twenty-five years.

Section 2: BOTTOM-UP VOTING IN HIERARCHICAL SYSTEMS
Description 2: Discuss the main question of measuring the democratic balance in hierarchical organizations using bottom-up voting and local majority rule models. Highlight different scenarios and case studies involving local majority rules, power inertia, and larger voting groups, and their implications.

Section 3: GROUP DECISION MAKING
Description 3: Explore the application of the Ising ferromagnetic model to group decision-making processes in social systems, including the dynamics of strikes and group polarization. Include detailed models and their implications for understanding group behaviors such as consensus and extremism.

Section 4: COALITIONS AND FRAGMENTATION IN A GROUP OF COUNTRIES
Description 4: Analyze the use of spin glass models to describe coalition formation and fragmentation among countries. Delve into concepts like random bond and random site spin glasses, and extend the models to include multiparty coalitions with Potts variables. Discuss similarities with physical systems and provide real-world examples.

Section 5: GLOBAL VERSUS LOCAL TERRORISM
Description 5: Illustrate the application of percolation theory to understand the phenomena of global versus local terrorism, emphasizing the role of passive supporters. Discuss the transition between local and global terrorism and strategic implications for reducing global terrorism effectively.

Section 6: OPINIONS DYNAMICS
Description 6: Present models for understanding opinion dynamics, incorporating factors like local majority rule, reshuffling effects, multiple competing opinions, and heterogeneous beliefs. Discuss the impact of contrarian and inflexible agents on opinion evolution and societal outcomes.

Section 7: CONCLUSION
Description 7: Summarize the key findings from the various models reviewed. Discuss the current challenges and future directions of sociophysics, particularly the potential for sociophysics to become a predictive science with established rules.