I'm very pleased to introduce Professor Samson Abramsky from the University of Oxford. Samson is a leading expert in several different areas of theoretical computer science and today he will talk about the fundamental aspects of quantum theory from a geometrical and logical okay thank you very much Olivia and thanks to all the organizers for inviting me to speak at this meeting it's a fascinating meeting well one thing I've picked up is a kind of theme that many of the talks sort of take topos theory into related to other areas so I guess we heard on Wednesday about sort of connections with wider areas of mathematics yesterday with the talks of Daniel and Jean-Claude we heard about connections with neural networks and today I want to talk about connections with some fundamental ideas in the quantum mechanics so we all know in some sense that quantum mechanics implies a fundamentally non-classical picture of the physical world and one of the clearest ways the sharpest ways that this non-classicality is expressed is in the phenomena of non-locality and contextuality and the famous results of John Bell coach and Specker theorem are the sort of most famous articulations of this now the main sort of message I want to convey in this talk for the for the interest of this audience is that the mathematical structure of contextuality and mathematically non-locality is a special case is fundamentally sheath theoretic it's it's fundamentally about the passage or obstructions to the passage from local to global so the non-existence of classical explanations for quantum phenomena corresponds precisely to the non-existence of certain global sections and this leads to both logical and topological descriptions of these phenomena very much in the spirit of topos theory so we'll use more with various times more or less explicitly a sheath theoretic language and and clearly the whole thing is in the scope of topos theory and a nice point about this is that it allows standard constructions which witness these results in which you find in the physics literature things known as for example coach and specker paradoxes hardy paradoxes and so on there are many paradoxes are frequently used term in this area to be visualized in a very direct way as discrete bundles and so there is a kind of topology here and in fact the non-classicality appears exactly as a logical kind of twisting of these bundles which is very directly related to classical logical paradoxes but also on the other hand there is topology there and it's witnessed by the non-vanishing of coma logical sheaf invariance so this harmony between a logical point of view and a topological point of view is very much I think in the spirit of topos theory and at the same time it's also strongly connected with probabilistic ideas and both quantitative and qualitative and discrete and continuous features arise naturally and again as I saying I think the very much in the spirit of topos theory to provide a home for all these different aspects excuse me samson we just see a page with the title overview is that normal oh my goodness no I there I've been seeing text can you see my text yeah yeah yeah everything is there right so this is everything I just said so okay now see the text as well okay very good all right so quantum context so yeah let me know if you're not seeing I mean I've got a lot of these pauses so let me know if you're not seeing text there should be text all the way all right so so most but so let's focus on quantum contextuality so I guess everyone's heard of bell's theorem I don't know how many people are sort of familiar and can give a well we'll see that very shortly so we know that quantum mechanics is weird as is often said certainly doesn't conform to our classical picture of reality and this has quite profound implications indeed for our conception of what reality is and also in terms of applications for the possibilities for information processing and we'll see something about that as well so it has both a very foundational but also potentially a very important technological application as well so what is contextuality so I like to encapsulate it in the following slogan in a nutshell contextuality is where we have a family of data which is locally consistent but globally inconsistent and you see immediately from this phrase that something about the passage from local to global it should be sheath theoretic and as we'll see it is sheath theoretic in nature so as a sort of helpful initial analogy suppose we were taking pictures of some building and we had a collection of pictures this is like our family of data and we see that each individual maybe our cameras and sort of isn't able to take a picture of the whole structure but we can take pictures of parts of it and we see that each part looks okay and even the places where they join up where they are but are consistent with each other so this is a locally consistent family of images but we would naturally think that these are all just parts of some coherent whole there's an actual building out there so we try and put them all together and we see what we see here is the famous Escher ascending and descending the power sort of visual paradox of a staircase that's either always going up or always going down depending on how you look at it so here is our global inconsistency incidentally as a side remark this very figure was suggested to Escher by Roger Penrose who studied with his father visual paradoxes and even associated a co-homology to these visual paradoxes quite akin to what we'll be talking about later okay so and then a very brief recap on quantum theory I'm not going to delve into this and I understand that people are not coming from physics this mostly in this audience but really this is just to reassure that nothing more is needed than some linear algebra because most quantum information and computation theory and also indeed foundational results relating to non-locality and contextuality takes place in finite dimensional Hilbert space so finite numbers of qubits or maybe q-dits if we allow more alternatives so a qubit is just a two-dimensional complex vector space that's the space of qubits and in general finite dimensional Hilbert space is just c to the n and we can just regard it as a complex inner product space so operators are just complex matrices and the adjoint of a matrix is its conjugate transpose so we can understand it very simply now what is a state of a quantum system in general it's a density matrix which is a positive semi-definite self adjoint probably trace one matrix and in particular pure states are just rank one projectors so we can think of it as a unit vector by the way we can just think of the one-dimensional subspace that it generates so when you prepare a quantum state the representation is just this simple object of linear algebra and when we measure projective measurements are described by self adjoint matrices and the idea is that the eigenspaces of the matrix in its spectral decomposition correspond to the possible outcomes of the measurement so and the basic rule that lets us compute probabilities that give the predictive content of quantum mechanics is the Born rule and the Born rule says that the system in state row will take the ith possible outcome of the measurement represented by the eigenspace p i with projector p i yes so when i said eigenspace is i was i was writing the projectors here that correspond to those eigenspaces so the Born rule simply says that the probability of getting outcome i is just the trace of row p i where p i is the projector on to the eigenspace and in the case of pure states and rank one eigenspaces this just reduces to computing inner products of complex vectors so there's just some simple linear algebra behind it when I talk about various observable behaviors that we'll discuss being realized in quantum mechanics we mean that we can find matrices of this kind which will under this Born rule produce this observable probabilistic behavior okay well i'm now going to sort of immediately come to some concrete example in fact quite soon we'll be proving some version of bell's theorem but so the the usual kind of way one talks about this in a physics kind of way is that you prepare a state somewhere remember a state is represented as we just said by one of these density matrices we have measurement devices Alice's measurement device Bob's measurement device we choose some measurement perform the measurement on our part of the state that's been prepared and observed some outcome but rather than talking in these terms there's another language which is very popular in the quantum computation and where we can even strip away this kind of physics speak and talk about a certain kind of game a non-local game or an Alice Bob game so in this eye in this sort of game we have two and this is mathematically isomorphic to the sort of experimental setup that we were just looking at so in this game we have two players Alice and Bob and they play cooperatively against a verifier but the constraint that's placed is that Alice and Bob can't communicate while the game is being played so that's the significance of this wall between them so they're put in different rooms we take away their mobile phones we close the rooms in Faraday cages there's no communication between them of course ultimately they should be space like separated so there's no time for light to pass between them during a round of the game and the verifier supplies Alice and Bob with inputs and they have to return outputs and if the outputs meet a certain winning condition then they've succeeded in winning the game so really the idea is to see what kind of coordinated behavior Alice and Bob can achieve given that each doesn't know which input the other has received so the most famous example which is very closely related to the usual kind of Bell's theorem setting is the XOR game so this is what we just said verifier chooses an input for each of Alice and Bob and we assume that the verifier choose it we're going to assume a uniform distribution was there did somebody say something um we assume the uniform distribution for the choices by the by the verifier of the inputs the convenience uh Alice and Bob each have to choose an output as we said they're not allowed to communicate and the winning condition in this XOR game so it's a funny looking thing that says that the exclusive or so these are all Booleans 0 or 1 and the the condition is that the exclusive or of the outputs should be the conjunction of the input so exclusive or is actually just addition modulo 2 so what does this mean if you think about it there are three cases I mean the conjunction is only true if both X is what one and Y is one and in all other cases it's 0 so in those three other cases the exclusive or has to be 0 as well so in that and that can only happen if A and B have the same value in other words if A is is the same as B if you think of addition modulo 2 0 plus 0 is 0 1 plus 1 is 0 and the final case so so those are the first three cases we see here and in those cases the outputs have to be the same they have to be correlated and the final case where this is true that's both X and Y or 1 then this has to be 1 and that can only mean that A and B have different values they're anti-correlated so the probabilities of the winning outcomes given the various inputs are given by this expression here and the success probability so a strategy a probabilistic strategy is just given by a table of conditional probabilities like this and if we assume a uniform distribution of the choices of inputs then the success probability for the strategy is just given by this expression so that's the XOR game so how well can we play this game well here is a strategy for the game so it's a table of 16 numbers so that each of these rows is one of these conditional probabilities conditioned on this choice of inputs to Alice and Bob and here we see the probabilities with which the various outcomes are obtained I mean we allow Alice and Bob to use randomization techniques as they wish just subject to this constraint that they can't communicate during the playing of the game so what this this entry highlighted here means for example is if the verifier spends Alice a 0 and Bob a 1 then with probability 1 8 Alice outputs a 0 and Bob outputs a 1 so I hope that is clear okay so we see a table of 16 numbers what can we learn from it firstly we'll learn a bit later that there's there's sort of a pre-chief here and there's something of that kind of structure but what we what we see immediately is that if we take the expression we looked at here for the winning winning conditions so we're looking at the the correlated outcomes in the first three rows and the anti that's the outside columns and the anti-correlated outcomes on the final row that's the two inner columns if we if we sum all those probabilities and divide by four to normalize we get a winning probability of 0.81 well is this big news yes it is big news or at least if we believe this thing can exist in the world it is big news because classically the optimal pro classical probability is three quarters so if the world behaves as it is supposed to behave according to classical physics classical probability then then the strategy couldn't exist I mean where do I get this three quarters from well in one direction it's very easy to see that we can do we can at least get a probability of three quarters for example suppose Alice and Bob decide beforehand they will both always output a 0 or they will both always output a 1 either choice is good then you see that in three of the cases they win because if in if the verifier sends them sends them any of the first three cases i.e. not both one then the the coordinated response the correlated outcomes are actually winning outcomes so if they put all their weights on those outcomes so so just a column of ones here and everything else zero then three quarters of the time they would win so that's a very dumb strategy which achieves a probability of three quarters of winning that is not only what you can do with a dumb strategy that's all you can do with with with classical means and that is less obvious and this this uses and is essentially you know they're essentially expressing the idea of bell inequalities which is the fundamental idea behind bell's theorem and the fundamental fundamental method in the whole of quantum foundations and quantum information and the subject of many experiments and of things that where people are of the emerging quantum technologies so this is a very fundamental idea that it's giving an actual limit to what can be achieved by classical means and which this strategy exceeds and since the table i just showed you exceeds this bound and moreover it's quantum realizable meaning that we can find a quantum state described by an entangled pair of qubits and and appropriate quantum measurements so we just find these matrices and according to the use the born rule to compute what what they do from the table and this would give you exactly this table of numbers so quantum mechanics predicts that we can construct such a strategy and as well shortly see this is confirmed by experiment and are already being woven into quantum cryptography there is kinds of quantum information processing scenarios so this is a clear case of using quantum resources to yield a quantum advantage in an information processing task okay so so let's discuss bell inequalities and this takes us to a pioneer of both probability and logic namely George Boole so Boole had a beautiful paper in the in the middle in the 1850s the 1850s still very worth reading and as was observed particularly by Ithama Petovsky what Boole was discussing there is essentially the subject of bell inequalities although of course he had a different motivation just looking at the fundamental question in probability theory so the problem is we're given rational numbers which indicate relative frequencies and if no logical relations obtain among the events then the only constraints impose although they each be non-negative unless the one but if the events are logically interconnected there are further equalities or inequalities that obtain among the numbers and the problem is thus to determine numerical relations among frequencies in terms of equalities and inequalities which are induced by a set of logical relations among the events and these are called conditions of possible experience so more formally we're given some basic events and some Boole which we can think of as variables and some Boolean functions which can be described by propositional formulae and we're given probabilities of the basic events and we're asking what numerical relationships can we infer from the logical relationship between the probabilities can we infer from the logical relationships between the events so this is already a beautiful interplay between logical notions and probabilistic notions and let's make a very simple observation which ends up giving a rather complete answer to this question so we've given some propositional formulas we're given probabilities for these this fits exactly into the picture we were just discussing and we make a very basic so to have some logical connection we say that the formulas are not simultaneously satisfiable they can't all be made true these are just propositional formulas so in other words any n minus one of them must imply the negation of the nth so now using elementary probability theory we we we can extract something from this we see that the probability of the nth events described by this formula because of this implication must be must be and the monotonicity of probability must be less than or equal to the probability of this disjunction and then by what is actually fittingly called Boole's a very simple Boole's inequality the first of the Bonferroni inequalities no disjointness but just the fact that the probability of a union is less than or equal to the sum of the probabilities we get this inequality we get the probability of a of a complement is just this we collect terms and we end up with this inequality just under this assumption that the formulas are not simultaneously satisfiable that the sum of the probabilities must be bounded by n minus one so this is a very simple derivation and we can immediately apply it to the bell table so here's the winning condition the winning outcomes winning responses of our XOR game highlighted and we have the probabilities waiting those outcomes in our table and so we make events that correspond to the winning conditions so remember this was on the first three rows that the outcomes are correlated and on the final row that they're anti-correlated we can describe in logical terms by these formulae so it's very easy to see that these are not simultaneously satisfiable if you take them all together they're contradictory so we start from A2 we can then replace it by B1 we can replace B1 by A1 and A1 by B2 and then B2 exclusive or B2 can never be true so they can't they're not simultaneously satisfiable so our little proposition from the previous slide must apply and therefore it should be the case that the sum of these these numbers that are highlighted should be less than or equal to three we have four events so n minus one is three but we see in fact that we get a violation of this bell inequality by a quarter so by the way I mean I had this isn't a contradiction in mathematics so there must be an assumption that I've made and you well I mean it's nice to think about this but the the I don't know if anyone wants to sort of say something here but in fact if you look carefully you see that I've tacitly supposed that all these individual probabilities come from a single joint distribution and that's really the classical assumption that there's a global event space where everything lives and everything is objectively going to happen you know I mean every everything objectively you know happens or doesn't happen regardless of which variables we choose to look at and under that assumption this goes through this reasoning goes through perfectly and would indeed give us a bound and then we'd see that this table is not consistent with those assumptions so we get a violation of this logical bell inequality and in fact this simple derivation has a natural generalization so given a family of propositions we say it's k consistent if the size of the largest consistent subfamily is k so if they're n propositions k out of n and if you have a k consistent family you can easily show the same kind of way that the whatever the probability assignments whatever joint distribution we have for some of the probabilities of these events is bounded by k but the interesting point is that all bell inequalities arise in this way so the result is that a rational inequality is satisfied by all non contextual input well as I'm not explaining all the terms but by all setups of this kind in very considerable generality if and only if it's equivalent to a logical bell inequality of the above form so in other words logic is controlling the the probabilistic what could be what can happen in terms of probabilistic behavior in this rather nice way so I think this does give a nice logical answer to bull's problem in fact pitofsky suggested that there might you know maybe in business that there could be such a result but I think this does give a nice answer and and if it also tells us that you know if if bull was delimiting the conditions of possible experience that in quantum mechanics we have quantum conditions of impossible experience and there's a lot one can say about that but of course the experience is impossible only in a certain sense because what's important to say in understanding what's going on here is that all that we can observe on a single play of the single plays of the game are just these subsets of variables we cannot observe all the variables together so the fact that there must be something true of all the variables at any point is the classical assumption and you can sort of see that this is going to lead us inevitably to something about you know non-existence of global sections okay so um is this all science fiction well I mean it's certainly a quantum theory is verified and confirmed in countless experiments and manifestations of our science and technology every day but very specifically these predictions were I mean there was a sort of history of experimental tests sort of turning back to the you know the picture of the preparing states measuring them and so on and this culminated just a few years ago one of the first widely agreed loophole free belt tests where sufficient time like sorry space like separation was achieved between the Alice and Bob measuring stations and sufficient efficiencies of detector efficiencies were achieved so that there was a sound basis for these results and this is a picture if you don't recognize him of John Bell who did this pioneering work in in 1964 and a review article by Alan Asper who was really the the pioneering conducting Bell experiments in the going back to the 1980s which sort of looked at these more recent teams actually three teams that did this did this work which as he says closed the door on this quantum debate so here you see a schematic where you have indeed a source emitting these entangled pairs of photons Alice and Bob now become detectors and then and they so they're performing measurements and we're looking at coincidences correlated or non-correlated as we were saying so this is actually done in various experimental setups by several teams so here's a sort of timeline the formalization with you know in finite dimensional case just linear algebra and then obviously with more general Hilbert spaces and operators and so forth goes back to von Neumann even to the late 1920s and every we've been using it since then the EPR paradox already in the 1930s Bell's there in the 1960s the first experimental test still subject to these experimental imperfections in the 1980s we already see the beginnings of quantum cryptography and of quantum computing in the 1980s shores algorithm of factoring primes in the 90s and these first loophole free bell test by these three teams and delft missed in the United States and Vienna in 2015 2019 quantum supremacy claimed by Google various other so this is to do with quantum advantage and an emerging quantum computing and technology industry right now okay so let's be a bit more formal and a bit more general just to give an idea of how we can connect to the sheath theoretic language so there's a kind of we can have a kind of level of types which set up the structure of a measurement scenario so I'm just going to look at finite things here so I've been saying so we have a finite set of measurements and then we have a simplicial complex whose faces are called the measurement context so this is telling us because the key point as we kind of already saw implicitly is that not all variables can be measured together only certain variables are measured together in quantum mechanics this is because you have in general you have incompatible measurements non-commuting observables so those that can be measured together are collected in the faces of a simplicial complex and then we have a finite set of possible outcomes for each each measurement and we have tables that give well so this is just the structure of a measurement it's saying what kinds of variables you have which of them can be can be measured together and that's all but then an actual behavior in such a setting and using which we can think of in terms of preparing some state and performing some measurements is given by what we call an empirical model which is a which is a family indexed by the faces of the simplicial context complex of probability distributions over these joint outcomes so these are the rows of our table as we saw earlier so the the simplicial complex here just has these these it's just a graph where we have these binary contexts and we'll we'll see more of this later but we can sort of visualize this in a very nice way as a kind of discrete bundle so we'll see more of that later let me just say that a key point here in in the sort of the underlying assumptions is that which is really enforcing this idea that well that the we that doing if you that we're not we can't our choice of context cannot be is not itself information that influences the outcome so in other words that if you have that marginals are well defined essentially if you have a smaller set of variables then whether you marginalize from one larger face or from another you get the same result so this is a physical principle generalized though signaling in the context of bell scenarios which relates to sort of relativistic constraints or in contextuality it's called the no disturbance condition so then we say that an empirical model as we just defined it is non-contextual if there is a joint distribution over this the whole set of variables which marginalizes to give us all these observable behaviors and that is we can glue all the local information together the the things we can directly observe by performing measurements into a joint distribution from which all the information can be recovered we call we call such a thing a global section and once we put it in categorical language chief language it is a global section as we'll see in a moment and if no such global section exists the empirical model is contextual thus this sort of makes more precise our previous slogan that contextuality arises where we have a family of data which is locally consistent but globally inconsistent and the import of bell's theorem and similar results is that there are empirical models observable behavior and indeed experimentally testable behavior arising from quantum mechanics which are indeed contextual so just to make a more categorical formulation given one of these scenarios we have a simplicial complex that we can define a pre-sheaf where the firstly this we have this sheaf which simply collects all the outcomes for each for each the as it were for each context each face of the simplex of the simplicial complex each sorry for each simplex in the complex we have the the local section giving an outcome for each of the variables in that context and then we compose that with the discrete distributions monad on the category of sets this is just to keep things simple the discrete distributions monad is just the reduction to the discrete case of the jury monad if you happen to have encountered this which is a basic going back actually to ideas of laudier which is a basic way of categorifying probability theory so it's a very useful monad that comes up a lot in many applications so this is a pre-sheaf and the restriction for this pre-sheaf is exactly marginalization and then we see that an empirical model which builds in this no signalling condition this physically significant condition is just naturality given that the you know restriction is marginalization the fact the restriction is marginalization just I mean this is obviously here trivially that we just have projections in this event chief and then just from the functorial action of this monad we recover that we get marginalization as the restriction operation so everything fits in a very very neatly in a categorical formulation and there's also a lot of topology at work here even if even in this finite setting there's a lot of topology at work here but I'd like to sort of firstly show you this in a visual form and then say a little bit about cohomology and variance so here is a way we portray these simple scenarios like in that Alice Bob game or Bell scenario that we were looking at earlier we have a base so we have a kind of bundle structure where we have a base with the variables and we put an edge between two variables if they can occur in the same context that that is they can be measured together so Alice can measure any of her variables together with any of Bob's variables and vice versa but Alice can't measure both her variables at the same time and Bob can't measure both of his variables at the same time so that's why we have the edges that we do above each variable in the base we have a fiber of the possible outcome so in our case here these were just binary outcomes in each case so we have these little fibers sitting above the variables in the base and a local section and and and the possible local section so here I'm abstracting from probabilities just to take those things that have non-zero that are in the support of the distribution that have a positive probability that could happen and so we only have we have edges that indicate those those events observable events that could actually happen and the global section here of possible events would be just in a path that goes around all the fibers in a consistent way and come a closed a closed curve that comes back and assigns a unique value to every variable globally so that's what the global section is okay so as we say we're so I'm going to look at another famous example from the quantum literature the Hardy paradox as it's often called and as we were just saying and the important point is that the contextuality here can be seen at the logical level without even invoking probabilities we only need to distinguish between what gets probability zero and what gets positive probability so I put ticks where there's a positive probability that's if you like it's possible and across for those with probability zero namely impossible so we have a basis before it's the same the same scenario the same shape as the bell test but it's a different kind of model as we said we have these are the compatible observables those are the fibers and then you see on the first row everything is possible so we put in all these edges on the second row only three things are possible so we put those three edges in and similarly for the other rows and now the point is that there are some global sections in this table here's one so that's a consistent value consistent with what lives in this fiber so the edges have to be things that we allow as possible events so there is there are some local sections but suppose we took a different choice of a local section here the question is can we extend it to get a global section and in this case you see we have a problem we can go forward and we can go forward and we can go forward but the only choice we have doesn't take us back to where we started there is no closed curve of this kind and that corresponds exactly to the fact that there's no way of extending this there's no global possible event which could account for this observable local event and this is already the signature of contextuality so and here we well we see in fact we can distinguish in this way different strengths of contextuality there's the basic probabilistic version that we saw earlier Hardy illustrates there's what we call logical contextuality where there are some global sections but some local sections that can't be extended and the extreme case is we call strong contextuality is illustrated by this as it were discrete mebius strip now this discrete mebius strip is exactly what corresponds to a famous construction in quantum foundations quantum information namely the Popescu-Rawlik box interestingly this is something that can't be realized in quantum mechanics it's even more weird than quantum mechanics allows for but on the other hand there are quantum realizable phenomena a little bit harder to draw which exhibit the same kind of strength of contextuality the point here is that wherever you start you can never get back to you never go around and get back to where you came from exactly you have to go around twice so you had there's no univocal unique assignment of values that that's consistent and extends any local section whatsoever so this is a mebius strip it's also in fact a well it's related to a lot of things let's see how it's actually related to the bell table the the XOR game the subject essentially of the bell test because those experimental bell tests were exactly confirming this kind of setup so really the winning positions in this game corresponding I mean if we just put you know only focused on those that would give us exactly the nodes we see in this mebius strip so that was what we were doing all the time and remember that the basis of our derivation of the bell inequality was that the corresponding propositions were logically inconsistent so we already see the sort of elements of a beautiful connection between physics probability logic and topology so let's say a little bit more about logic so in fact you know there's the famous lie of paradox the sentence that says I am false or this sentence is false by extension we can take liar cycles this is the sort of thing that magicians study where we have a sequence of sentences which each says that the next one is true but the last one says that the first one is false so and these liar cycles can be modeled by systems of equations so that the point about doing these cycles is that we see with that each of the statements involves a subset of the variables and when you each individually or in fact any n minus one of them are consistent but if you take all of them then you get an inconsistency and in fact um uh up to rearrange but the liar cycle of length four corresponds exactly to the PR box and the usual reasoning to derive a contradiction from the liar cycle corresponds precisely to the attempt to find a univocal path in the bundle diagram and of course this can all be discussed much more generally but I think this already shows vividly the uh connection and for those of you sort of uh familiar with logic one of the famous results of first order logic Robert is Robinson joint consistency which is an equivalent of the kreg interpolation lemma which says that if you have theories over different languages which are consistent modulo their common sub language then the union of the theories is consistent so this is you know you can turn this around into kreg interpolation now this is um it says that two compatible theories can be glued together they're compatible in the sense that they agree on their overlap they don't disagree at least on their overlap in this binary case local consistency implies global consistency what you will never see in any logic book is something that goes beyond the binary case and that's for the very good reason if you go beyond the binary case it fails uh and actually you get a minimal counter example just even propositionally by taking these three theories and you see that they're um locally consistent in this pairwise consistent but but jointly inconsistent and this is actually or again something that occurs famously in the quantum foundations literature this is the specker triangle from his 1960 paper preceding the famous paper with Simon Cochin okay and then a little bit about the co homological characterization um there is topology here and we can witness contextuality by co homology so i mean i'm just gonna i'm not gonna go into details on this but i mean it's really fairly simple we're just witnessing the non-existence of global sections so this is meant to be a sort of a support uh pre-sheaf um and we can um we take a relative co homology so we focus attention on one context so this is like starting with one of the local sections and seeing what happens and um uh we can uh we can assign to each local section here an element of the first co group in the Czech co homology uh which we work with because it's easy to compute with uh and in fact gamma is really just the connecting homomorphism of the long exact sequence so there's some choices here and these are exactly the choices you make in uh you know non-essential choices you make in um uh proving the snake clone i say okay so then and then the basic results are indeed that you know as we would expect that um uh the the co homology obstruction vanishes is equivalent to there being a family which extends the given local section so if the model is uh extendable in the in the sense we were just saying to start from a local section always go to a um a global one that that extends it then the obstruction vanishes so if the um uh so what this is saying is that non-vanishing of the obstruction uh which was the quantity we just defined there in the first co homology group provides a co homological witness for contextuality so um now this this sounds perfect it's great but of course the the sort of drawback is that to get to get going we needed to abelianize by taking not the supports themselves but the free um free the the module that they generate that we took over the integers um so we're abelianizing and where we have these integer coefficients um and because of negative coefficients in co chains you know sort of weird things that wouldn't that we don't really care about there are false positives nevertheless we can effectively compute witnesses for contextuality in many of the cases in the literature and in cases where the outcomes themselves have a module structure we obtain very general results so-called all there's nothing proofs which actually accounts for most of the contextuality arguments in the quantum literature and in particular we can find large classes of concrete examples in stabilizer quantum mechanics and we have a complete characterization of contextuality there um now there were these counter examples of my my student Giovanni Caru that's a beautiful work in his thesis and he has a paper I'll mention at the end which gives a refined co homological criterion which covers the vast majority of cases kills all known counterexamples and is conjectured to be complete in fact and following our work Robert Rausendorff uh um leading figure in quantum uh information and uh Cihanoke have developed a related co homological treatment of contextuality because some of what they've done my students even Osnes has shown that their work also uh sort of falls under the scope of the chief co homology invariance and okay Cihanoke in particular has done a lot of work in applying topological ideas in contextuality and quantum computation okay so I hope I still have 10 minutes left is that right Olivia or yes yes yes okay thank you very much so um yeah okay so that's something about co homology I mean I uh if you want to I'll I'll give some references at the end now I want to turn to a sort of some geometry some another different aspect this is a multifaceted subject so another facet is convex geometry um which is also very rich here so we can um if so here we think of these probability tables so think of them as vectors just they're just vectors of real numbers of probabilities sort of lay lay the table out as a vector in a high dimensional um r to the n uh and then um what we find is that the spaces of these uh probability models under various assumptions form natural convex bodies in this euclidean space so in particular because we have bell inequalities linear inequalities which which bound all the possibilities for the um non-contextual models they form a polytope and then on the other hand if we only impose the kind of uh there's no signaling kind of conditions the marginalization conditions those are also linear um linear equations uh linear inequality uh linear inequalities because you also have a non-negativity constraint so they also form a polytope and these things can in principle all be found by linear programming although the linear programs get big very rapidly of course and then sitting in between these two uh the non-contextual case and the um no signaling case we have the quantum set those things that are quantum realizable by using quantum states quantum measurements and computing probabilities using the Born rule as we mentioned it's a convex set but it's very definitely not a polytope and we can relate the various hierarchy of contextuality that we've mentioned to the geometry of these polytopes so obviously the things that the interesting things from our point of view are those that lie outside the non-contextual polytope that violate some bell inequalities um and uh the um so that the whole space of of contextual models lies in in this sort of area here but the most interesting of course for us are the quantum realizable ones which lie in this quantum body cube um there were a strong contextuality in general lies at the vertices or at least the faces of the polytope containing only uh contextual models and the um uh in lower dimensional subspaces and the logical logically contextual things like the hardy paradox in faces of this polytope so we get a high a strict hierarchy in fact as we were saying of these different kinds of contextuality and this classification in turn feeds into uh things we would like to do in relation to quantum advantage as an interlude i can't resist mentioning that although it you know you may say everything is finite and it can't be that hard that there's a huge amount of complexity here just consider the question given a finite probability table as we've been showing a finite table is there a quantum realization is there a quantum state and measurements which give rise to it via the Born rule if we fix the dimension of the Hilbert space this reduces to the existential theory of real closed fields it's a it's a it's a it's a it's a fine it's a finitely it's a finite search problem although we're searching for complex numbers but searching for complex but a given a fixed number of complex numbers which really means a fixed number of real numbers and that's that isn't so bad because we know already from Tarski um and then uh since we only need existential queries from later results that um this is a decidable theory and in fact decidable in peace space so at least it's decidable albeit of uh high complexity but if we ask the realization in any finite dimensional Hilbert space so we're we're no longer bounding the the sort of number of complex the size of the matrices we need to find then this is undecidable and moreover rather fascinatingly there are finite tables which are realizable in infinite dimensional Hilbert space but not in any finite dimensional Hilbert space and this already comes from beautiful results by William Slopstra published quite recently but going back a few years earlier we has a beautiful reduction to group to group theory and computational problems in group in group theory one can use the Higman group to show this latter fact for example and even more spectacularly we have the recent result with a great title if you're of MIPSTA equals RE the result of the G Natura Jan Vidic Wright and UN which is simultaneously a major result in complexity theory quantum foundations and mathematics so MIPSTA so so we have this paradigm and complexity of the interactive prover paradigm which is famously equivalent to peace space and even if you if you if you give the the prover quantum resource but you only have one then it's still peace space by a famous previous result but if you allow multiple quantum provers sharing entangled space then it allows all semi decidable problems to be represented so for example the halting problem provability of statements in piano arithmetic and so on so it already becomes really strong so and as consequences of this it refutes the Terylson conjecture which really says in a way that tensor products at least in infinite dimensions are not fully general to describe you know they're no longer equipped I mean so if you have commuting subalgebras of two subalgebras of operators where one subalgebra everything one subalgebra commutes with everything in the other in finite dimensions you can always represent this on a tensor product and this is no longer true in infinite dimensions this is essentially the Terylson conjecture and the very famous mathematics conjecture of Al-Ancon 1970s is is also refuted by this result that the connection between that and the Terylson conjecture was already there so there are some quite very deep and remarkable phenomena lurking in these settings already okay so to say I'm running out of time yep so I'll just say that you know this does reach into issues of quantum advantage and using these tools that we've been mentioning to derive a general results about quantum where you can gain where you can do something using quantum resources that you provably can't do using classical resources and this is you know it's an emerging technology which it's pretty clear is going to have a major impact on our scientific world technological world and beyond and we still have we have remarkable examples but no general theory so we're beginning to develop some elements of this or that's the aim so here we we have a way of measuring contextuality and for a large class of problems we have an inequality that shows that to get a better a better performing algorithm you need more contextuality and in various cases you need some of these stronger forms of contextuality that we were we were mentioning so this is and really the the sort of a major current topic of interest is where to where the line in the sand can be drawn separating quantum advantage using these non classical phenomena from efficient what is efficiently classical simulability classically simulable and there's there've been many surprises in both both directions so a very promising recent line of work is is in shallow circuits breakthrough work by gravie gossip and cunning which gives an unconditional separation most most separations you'll see are just based on the best you can apparently do or or on in theoretical work on using conjectures about separation of complexity classes but they give an unconditional separation for this shallow circuit class and the idea of the shallow circuit class is that the non locality as we saw earlier is weakened to a bounded locality so shallow circuits mean the circuits can get arbitrarily big but they can get wide but not deep each circuit can only have a bounded number of sort of previous gates or each gate can only have a bounded number of gates feeding into it previously computed so this means that in a classical circuit most things can't communicate I mean they don't have to be placed like separated but they can only communicate through the structure of the circuit but in a quantum case you because you have this this correlation behaviors as we saw earlier you can achieve a provable quantum advantage and although the the sort of absolute locality is kind of attenuated by this this bounded communication that you have in the circuit asymptotically the advantage witnessed by the bell inequality violation is recovered so this really leverages all the tools we've been discussing to prove a striking result about what could be achieved with quantum advantage of course the point is rather than a single finite case we now have a whole family of instances a circuit family and so we get an asymptotic calculation there and the same ideas hopefully can be transported to other computational settings and there are a lot of other further developments there are remarkable rockably good connections with things that have nothing to do with the quantum mechanics for example in relational database theory and in even in linguistics and so on and something it's been a pleasure for me to find out recently is there are strikingly close connections to work done by Daniel and his students and collaborators from I think quite different motivations essentially but the mathematics is strikingly reminiscent so something we hope to understand better let me just give some references to papers that will be published in various places but you can conveniently access them on the archive and they want to get more details of anything I've been talking about you can find that there and here are some of the people I've had the pleasure of working with on these things so thank you very much thanks so much for this marvelous talk


Although Roma are the largest ethnic minority in Europe, they still experience high level of racism and have to deal with many societal issues. Additionally, Roma are being represented in a very stereotypical way in the media and artwork. The Roma theater has more than a century long past with a lot of active professional theater groups in many European countries, but unfortunately, they are still hardly known. The Roma Heroes Theater Festival initiated by the independent theater Hungary is the only international Roma theater encounter in the world which have been organized in every year since 2017. Some of the present artists and their work are introduced in our series. Today, my guest is David Schwartz, the director of the play called You Haven't Seen Anything and Alex Piffer, the author and performer of the play. Hi guys, how are you? Hello, hello. Okay, so I will start with the first question and it's super simple. Please, could you briefly summarize what the play is about? Well, our play investigates means and the terms in which Daniel Dumitrake, a young man of 26, has been murdered in the police station, number 10 in Bucharest, Romania. And it is a story of this young man who has practiced something very usual here in Bucharest, which is for people who don't really have opportunities to get jobs and proper jobs. They practice the street service of parking cars. This guy, Daniel, was only 26 when he was restrained on the street by the police. Which actually knew the person, knew his occupation and they dragged him to the police station where he got beaten up and he deceased and he died in the police station later that night. Well, we investigated, and documented the whole thing. And we followed the legal process which took place. It was a long, long process and then after a few years, the policeman responsible, one of the policemen involved in this tragedy, got sentenced to seven years of prison. Of course, we launched the play while still in process and we tried to investigate the particular circumstances under which this happened. And we got to talk to the family, talk to everybody involved in the crime.  Yeah, David, the director, he directed it and he could also tell a little bit more if he feels necessary. I think it's what is important to mention is that in our process of research, we discovered or we found out what we had already in some way suspected that it is this intersection of ethnicity and poverty that bring this, that brought the situation, that brought the situation, of Daniel Dmitrak's death. So basically the police is profiling Roma persons and also profiling impoverished persons.  It is many times Roma people or people who look Roma, so looking darker skinned people. And it is also very much class discrimination. It is more or less the police is actually doing the job of cleaning, the city where cleaning means punishing the undesirable persons. In this category we get all kinds of informal workers from parking attendees to sex workers to other groups of people that don't match so to speak with this official people in the picture of Bucharest as a city of, actually it was a city of the middle class or as a city of the elite. So it is this intersection of blood and racism and the class discrimination that leads to this sort of tragedies. Thank you. I had the chance to see the play already in Budapest and it was very tough. Alex, you also perform in the play. Can I ask you what's the most difficult or challenging part for you? Of course it was getting in touch with the family. That was in the process of documentation that we had on display. And yeah, I guess that was the first part where for me it was when this happened and the play was one of my first experiences in social and political theater. And it was maybe one of the first times when I really got to have a direct discussion and get in touch with the real thing on the street as a documentary. And it was the first for me and the real grief of the family of course was the thing that was for me in that moment a little bit of a shock, because that's what the play does. It goes into details with not very nice things that can happen to impoverished and to the poor and to the Roma of course. Well, besides that, I don't know. Yeah, I guess I'm really connected with the family because that's what impacted me the most in the documentation. So when I get to play the family and especially his cousin, that's where I feel it the most powerful connection. Yeah, I guess that's it. Thank you. Okay, so now it's a question to both of you. Could you please share a few sentences about your artwork? What is your art creed? What are your principles in your artwork? Well, for me, I'm no longer a beginner in this kind of theater and I guess this is what I will do as a professional for a long period of time from now on because this is how I really get to be in the society and to represent myself. And by representing myself, my values, my political views, which are related to the human, related to Roma tradition, related to the story and the, how to say it, the poverty issue, I guess these are my three directions in which I want to investigate and go deeper. Of course, it's always the new forms of practicing it in theater that I have to be connected with and be in charge somehow. It's discovering new forms of expression that go a little bit further than the classical ways of making theater. David? Yes, as Alex mentioned, I also see myself as a political artist and I see theater as a means of expressing political ideas and achieving, if possible, a sort of social and political change in the society. So I am very interested in the contradictions of the present-day capitalist society and of the different conflicts and tensions that appear in this society. And at the same time, I am not doing this from an objective position, but I am doing this from the, trying to deal with these issues from the subjective position of the persons who suffer the consequences. So it is a sort of, even if it is sort of doing the theater that is not only about the oppressed persons or categories, but this is in some way analyzing the relations of oppression and the relations of power in the society, but from an, let's say, emancipatory perspective. I'll try to sum it up shortly. Thank you. I would also ask both of you what motivates you, like what are, and who is inspiring you or inspired you in the past and not just in your career, but also in your life. Well, tough question, because I guess what motivates me is the need, the need of reaction, the need of saying things, the need of protesting, the need to let people know of a different story than what is offered by the classical ways of communication. Even the news today, I don't think they really are the news. I think we are fed up with this official story. And it is kind of being alternative. It is the need to dig deeper than what is offered by official channels. That's similar for theatrical and politics, you know. Of course, in the beginning for me, I just told you with this play, particularly, it was the first real occasion to go out and really take, go into action, you know, start documenting, start being what it means to be a political actor. And for me, it really was David Schwartz that first got me introduced to this, it was his place where I first got in touch with this political theater thing. And this got to represent myself also. Now what motivates me is also the need for my kids. I have two kids and they're still young. And I kind of try to offer them a different perspective also, you know, with what I do, with what I try to build up here with my profession, so to say. Yeah, I guess that's it. Okay, so first about what motivates me, I guess this motivation comes from two complementary factors. It is the, okay, so I'm sorry, I have to stop for one minute, but I'm coming back. Okay. You need to do some editing. It's not just me. You have to edit more than one. Alex, did you fill in the time or no? You're okay. Okay. So regarding my motivation, yes. It comes from two complementary factors. First is sort of indignation towards the situation of the society, which you can see in everyday life, in every aspect of my family, of my community, of the city where we live in. And now as we live in sort of a global, in a global village, you can see it, if you want to be a little bit conscious and a little bit well-informed, it's obvious that there is a huge disparities, contradictions, and struggles in the society are bringing us to a sort of moment of crisis. And the experience we all had this year with this pandemic situation is only exacerbating something that was sort of filling in, sort of a feeling that you could have in the society. So first is obviously a sort of need to contribute to a change for the better because the situation has become sort of unbearable. And the other factor is also a sort of, it's sort of a tradition. Also in, so there is a left-wing tradition in theater and there is a left-wing tradition in politics that sort of inspires and inspired me for many years already. And yeah, regarding sources of inspiration, I have had, I have so many and so different and it's, when I have met people who got evicted from their homes and we struggled together to support their fight, their struggle against evictions, this has inspired me a lot in my work. It happened when I was a very young artist. It inspired me a lot in my work and those people inspired me. What I have met people who are now 90 or 95 years old have been part of the anti-fascist resistance in the Second World War. This has inspired me a lot as well. But on the other hand there is a whole tradition, a political theater from Bertolt Brecht and Erwin Piskator to present day artists who also inspire me quite a lot. So there is a big range of inspirations and also deep motivation that comes from the structural context in which we are in. Thank you. Before my last question I would also ask, what do you think about Roma theater, Alex? What does it mean to you? Do you consider it necessary to have Roma their own institutions? Or what do you think about it? And also, David, be free to add your thoughts. Well, the problem with the Roma theater is let's put it this way. Romania has a long history of Romanian romans. Do you have a long history here in Romania of oppression? I mean, just for the record to say so. Roma have been slaves in Romania for 500 years. 500 years history of the meanest and toughest form of social exploitation by human race. It's 500 years. Not until now, it is just 150 years when the abolition of slavery happened. No compensatory measures have been taken by the state. Not at that time, not even to this day. The state has not recognized the slavery, the history of slavery. They are not recognizing maybe in the last years they tried to kind of mind that they do so by mentioning the Roma as a holocaust victims, you know? And bringing things to this day, there is no state theater for Roma actors in Romania. Budapest has one. Everybody has one. Other communities in Romania have it. And we are talking about, for example, the Jewish community, which is somewhere David could tell us more exact figures, but it's something related to the thousands, maybe. There are 100,000 people in Romania and they have state theater. Not since now, but since 60 or 70 years ago. I hope I'm not getting the figures. 71. 71 years. Okay. Roma do not, and I repeat, do not have such a state theater. It would be an obligation, a moral obligation for the Romanian state to offer the conditions of having this theater. But this doesn't happen. And this is not the only thing. Roma actors in Romania are only a few hand of people. Why? Is there access to institutions? Why? Two million people in Romania. Two million Roma people, a huge community. Well, that's the most pregnant tissue of the Roma theater. In these conditions, all we can do is build up identities and build up theater communities. And this is not possible if there is not understanding and acceptance within the members of the community and having a common goal, which should be, I think, instituting this important presence in the cultural life of a country. You know, this is what upsets me the most. The non-existence of this state theater. Well, we'll have to do it on our own. It is only a problem of building up a force strong enough to demand that and strong enough to even create it by itself. Of course, this is beautiful theory. And until this happens, a lot will have to be done by particulars, Roma actors. And by that, I mean Roma actors that have to build up communities that have to bring up this issue until it's solved. And this would be a recognition more than necessary from behalf of the state. This is my opinion. Thank you. Lastly, I would ask you, what is your future plan? What are your future goals in life regarding the career, your career? And it's a question to both of you. I think now it is more than ever a problem of surviving as independent artists. And for me as an independent artist, surviving is what I did before. Surviving before the crisis, I mean, the pandemics. And surviving it will have to be from now on till, I don't know. You cannot really tell in this time what will be within the next six months because of this huge, huge health problem that we are facing. But on a long term, of course, I will keep making social and political theater as a mean of living. I don't know, as both a means of living and a personal statement. Thank you. Yes, for me as well as now, especially in this time that everything is so uncertain, I think we must reflect more on what are our long term goals and objectives. And it is also a time of reflecting upon our past and what have we done so far, what has worked, what hasn't worked. So it is sort of a moment of analyzing and of a moment of uncertainty, which I think we have to assume and to reflect more and maybe project less or project more in terms of goals than in terms of projects or particular projects. So just as main goals for me, of course it is very important to continue my work as a political artist and as a member of a political theater collective. But on the other hand, I think more and more about pedagogy and about how to transmit things to a next generation and how do we do that the political theater that has emerged in Romania with quite a big success in the last 10 or 15 years, how do we do that? It will not be just a fashion of a generation, but how to make it a long term an institutionalized way of making theater and relating to society and to the problems of the society. Thank you. Okay, so thank you for the discussion. It was very interesting. Now you can see the performance called You Haven't Seen Anything directed by David Schwartz written and performed by Alexi Fer. Enjoy the show. Thank you for the opportunity. Thank you. Thank you.


Shimshon Eat Jerusalem presents Shimshon's Hanukkah Souvkanaya adventure. Hi guys, this is Shimshon Leshinsky reporting from Jerusalem. We're near the end of Hanukkah and we have to do our traditional Hanukkah crawl, tasting different delightful donuts. So we've come to the best of the best, the Kadosh bakery. It's the most expensive, the most glamorous and they've got about 15 different donuts we're going to try two today. Saladhof is a very simple Barakus place about 30, 40 years ago and then about 10 years ago the younger generation changed the whole thing and made it very glamorous, a kind of French-European style. So let's go in there and eat these glamorous donuts. This is our chance to say Lechaim for you and all of myself. We want a lot of things, we want peace for yourself, we want Shim to guide our soldiers, our hostages and we went back to stability and normality. Lechaim haqsamaya. Strong. Hanukkah, you know, Habuk Hanukkah for everybody, celebrating, all the Jews are celebrating in Israel. So we make the donuts here up top in the Kadosh area. So we have here Pate Sier Frim with marmalade. Marmalade? Yeah, marmalade, sorry. It's a bit special marmalade, marshmallow with a raspberry and dry raspberry. Marshmallow, blackberry? Okay, I have here Kevlova. Kevlova with a jam. Kevlova jam. And breaks of meringues. Meringues in it. This is coffee cream. Coffee cream. This is mixed berries. Mixed berries. This is chestnut. Chestnuts. Put a little doughnuts that cover with caramel. Now that Jim Sean had become acquainted with all the delightful doughnuts on offer, it was time for him to make his choice. Jim Sean picked out two doughnuts to sample and see if the quality of Kadosh's Souvganeot lived up to the fancy decor. Should we open the box? Should we live beyond the box? Let's do it. We've taken two out of about 12 or 15. We've got here the Kevlova and we've got here the chestnuts. It's all very fresh. It's just all happening. It's exciting. You need a coffee with that because it's very sweet these things. And we're doing the mitzvah of celebrating Kanoko. The place is packed. There's lines to get in. Lines for everything. People jostling. And now we're doing it. Let's try the first one. Okay, we're doing the chestnut one now. It certainly looks beautiful. It looks interesting. They have a unique way of packaging it. The competitor, English Cake, tried to make doughnuts that look the same way but it didn't taste the same. Wow, they're generous. When I was a boy, it wasn't generous like this. It was just a big bread roll with a tiny teaspoon in it. We'll try that one. Fresh, delicious. You can taste the chestnuts. Very soft, fresh doughnuts, a nice cream, you know. So easily we'll give this nine out of ten. Now we'll just try this little topping here.  So it's a bit of a glaze. It's a bit of a decoration. Quite nice. Doesn't really, no chestnutty thing there. But overall now we're going to move to the Pavlova, which is something from Australia and New Zealand. Named Pavlova originally was made by famous ballet dancer. But we need a bit of coffee between, you know, not to mix the flavors. Now we're moving to the second one, the Pavlova. We're cutting it in half here. It's got meringue. It's got some cream. And it's got some jam. So we'll see how that's doing. Quite a nice filling here. I can taste the kind of Pavlova feel to it. Delicious, great. This is nine and a half. This is even better than that. So the chestnut was good. The chestnut flavor wasn't as dominant as I would have hoped. But really we've come to the best place. Kandosh is 19 shekels free. The doughnut is very expensive, but delicious. So we hit the jackpot. You should get here fast because after Hanukkah the whole doughnuts of Kaniyia's team dies out. Cold in Jerusalem today. There's a lot happening. We're doing doughnuts of Kaniyia taste things, just as Hanukkah nearly finishes. And it's a festival about bringing in their life with this darkness. And Israel has gone through terrible times, traumatic times, probably the most traumatic since the state of Israel was established. But there is hope. There's people helping each other. There's people together. And of course there's restaurants and food. As Jews always need good food. We've had our latkes. We've had our doughnuts. We've had our spinach. So I'm feeling positive about the future of Israel. So we look at the past and we look at the future. It's all connected as Jews. And we feel that there is light, that there was darkness. And we've had a terrible catastrophe. But I believe in Israel. I believe in the Israeli army. And even though a lot of the politicians are problematic, overall the people know what to do to run this country the way it should be run. So I miss Elkhai. We're hoping for the good future. It might be in one of the amazing places. They do interesting doughnuts. Fresh, beautiful colors and flavors. They're very popular. Sometimes you can't get in here. I've had this one. I've had the regular strawberry and I've had the regular caramel. And they're both fantastic. In fact, they're bought 100 early this week. As doughnuts picked out, Shimshun was ready for a second round of reviews. We've got two here. We've got the gold one and we've got the chocolate one. It's got fancy ingredients, fancy names. We'll try a little bit of each from Roche or the gold nut. What do you want to start with? Ferrero Rocher. Ferrero Rocher is a chocolate which is very popular in Israel. It comes from Italy originally. And also the Nutella chocolate spread comes from the same factory. It's chocolate and hazelnuts. So we're going to try a bit of this. It looks amazing. Really, for chocolate lovers like me, this is paradise. Oh, it's going to be messy, this one. It's hard to cut. Oh, there's different things inside as well. That's the thing about, well, they put lots of different things in it. Different spreads. There's about five different ingredients in here. So we'll try this and see what happens. Soft, fresh doughnuts. Lots of different chocolates and nuts and layers and spreads. Very sophisticated. So definitely I'm going to have to go for the 9.5 out of 10 as well. In fact, 9.5 out of 10. The pistachio one was even better I've had here before. Donut two. Okay, now we're quite here. It's a gold nut one. The owner, Asher, recommended it. So we're going to cut it inside and see what we get here. These doughnuts are very sophisticated. Lots of layers, lots of different things. Not as much filling as I would have expected from a roll of doughnuts. Yeah, in fact, it doesn't look like there's enough filling here. This could cost them the Sifgania victory. That's right. I mean, they're fighting. Oh, there's a bit more here, but not enough. I think they should have been more generous like in the other ones. We'll try this one. There's nuts and cream, but it's quite got a custard sauce into it. Not enough filling, you know. Somebody stacked off. Somebody had too much to drink the night before, I think. So it's still decent. It's still nice, but it's going to go down to an eight. So for Sifgania later, and the result of Sifgania's crazy doughnut extravaganza are in. Kadoosh got a nine and a 9.5 from the food reviewer, giving it a total of 18.5. Roladine got off to a great start with 9.5 on his first Sifgania, but fell down on doughnut number two, which according to Sifgania just didn't have quite enough filling, giving it a total score of 17.5. The victor in the Jerusalem doughnut runoff for Chanukah 5784 is none other than Kadoosh Cafe.


Welcome back to our channel. My name is Andrea and I'm Howard and we are with Food and Mentory Adventures in Food. Our channel is all about the food. We do taste tests, grocery hauls, recipes and what's for dinner and we are back today with an unboxing from Indonesia. Yeah universal yums. So if you're not familiar with universal yums once a month they send you a box from a different country with their most popular snacks and this month is Indonesia. So I've never tried anything from Indonesia that I know of. I don't think I have either. So we're gonna jump in. I think this box it's either $19.99 or $25. I can't remember which but we're gonna we're gonna go ahead and get started. All right first thing up is presto corn. Okay. Or presto corn. And while he is opening that box I will tell you that with every single box they give you a pamphlet of everything that is in the box and they also give you fun facts about that country. They usually give you a recipe too and so there's a description of every single product that's in the box along with snap shots and things from that country as well and trivia and all sorts of here it is trivia all sorts of fun things so. So I thought this is gonna be popcorn but it's more like. Corn nuts. Corn nuts. Yeah. I like corn nuts. Maybe you like these. It says. Try to see what it says about it. These are garlicky corn nuts. Okay. So that might be pretty good. Cheers. Very garlicky. Mmm. That's good. Yeah. I like those but I do like corn nuts. So if you like corn nuts and you like garlicky stuff you'll probably like those too. It's not bad. Not bad. Okay. So the next thing that we are going to try are these tic tac snacks. Grilled beef flavor. Oh these are it says tapioca snack. So there it is. Tapioca snacks. Yeah it seems strange. Yeah and I'm not a big fan of tapioca. Aren't those those little ball things that come in the like yeah those Asian drinks and stuff. They say it looks like a breakfast cereal but don't put milk with these because that savory beef seasoning. It has an odor. So let me I don't know. Here's what they look like. I don't know let me try to show you one. Little balls.  I'm not eating all of them. I'm just eating one. Alright. Cheers. I don't really have much of a flavor. Yeah but I can do without them. Yeah there is it what is it. I don't know what this is. Beef flavor. I don't care for it. It tastes like a the texture is kind of like the kicks like the kicks cereal. Yeah okay what's next. Alright we have this mannello mannello layer cake. Okay and it says it is a pandan flavored layer cake with cream filling. Light earthy aroma. It says it's green. It says it is the vanilla of the east. I probably don't think I will try this one or not. You hear green and you don't want to try it. I hear green and I don't want to try it. Plus I'm really I'm really not a spongy cake person. I'm big into textures and that. No I don't think so. So the topping kind of stuff to the bag the brown parts. But it is green. It's like a green sponge cake. You want to have a little piece or no? No thank you. Alright. It says it's green in flavor too so that's just a double no. It has a little something in the middle. Yeah. Alright I'm going to try it. Okay. I'll take one for the team. Here it is. Whatever that vanilla is that's what's making it green. It's like an herby kind of a cake. What is it? It tastes like sponge cake with different flavor. It's not bad. Is it green? Is it like a green herby flavor? No. I can't explain it. I don't know but it's fine. Welcome to my life. Okay. Next thing that I'll try is this cheese wafer. It's a jumbo cheese wafer. It's a jumbo cheese wafer and we actually got two in the box but we're just going to open up the one of course. It's a cheese and cheese wafer roll. To me just hearing that. Excuse me grab scissors. It sounds like a combo which I don't like. Do you like cheese? Do you like cookies? How about cheese cookies? Okay. So do you guys know what combos are? They're those hard things and they have like cheese in the middle. Oh yeah I like combo. Okay so this is very crumbly. I think it kind of broke apart. I'm going to try to show you guys. Can we take off? Can it come out? Yeah take off. So this is what it looks like. Of course it was a longer roll but it's very crumbly, very kind of like filo but not but it's I don't see the cheese. I can't show you the cheese on the inside. That's what it looks like. Ready? Cheers. Very cheesy. And sweet. That's a no. I like it. That's a no. Let me finish yours. Please do. I don't think it is. That's what it tastes like. It tastes like a sweet cheese like a cheese cookie but it's wrong. It's not right. Okay your turn. Alright next up is Bang Bang White. Looks like some kind of wafer. Yes it says a white chocolate and coconut coated wafer with cream filling. That sounds good to me. Yes it says coconut inside four layers of crispy wafers three layers of cream rich white coconut outside covered in coconut. This is the country's most plentiful crop. Oh look at that. There's a little tray in there. Yeah coconut everywhere. Coconutty. Let me see if I can take it out without making a mess. Nope I'm going to make a mess. Okay. Oh alright I think I got it. Interesting. Oh it's kind of, let's see. Alright I'm going to have a little piece. Yeah. Oh it's harder than I thought. Oh it kind of looks like a Kit Kat on the inside. Let me try to. There it is. See it kind of looks like a Kit Kat. Oh and the bomb is like white chocolate. Ready? Cheers. It's not bad. It's a little different. It's not bad. I taste the coconut. It tastes like a Kit Kat to me with coconut. I like it. And white chocolate. Whatever it is. Okay. So the next thing that we're going to try is this, it says coffee joy. It just looks like little cookies right there. And I'm going to open it. See coffee biscuit with sugar topping. Oh something multiple. So I open up the box and you get two of these little packages in the box. So let me open it up. Thank you. I don't know if this tastes like coffee. I don't drink coffee but I like coffee candy. Well let's see. Oh they're very thin. Very thin. Try to get them out. You know what it looks like? A graham cracker. Can you hear it? A very thin wafer. Yes. Like a graham cracker but even thinner than a graham cracker. Smells like coffee. Don't you think? Yeah. Cheers. It tastes like coffee. Yes it tastes like coffee. Did you say no? No. There's a mild coffee. Yeah there's a mild coffee flavor. Yeah I got the coffee. I would. I don't like coffee but I would eat these. Because they're super crunchy. Kind of like a graham cracker. Let me show you. This is how many comes in one little box. Yeah it seems like a lot. Yeah not bad. Pay your turn. Okay. So I'm going to try now cassava crackers. Cassava crackers. Let me find a description. Okay. So these are black pepper cassava crackers. Let's see. He didn't like black pepper. The cassava shrub is an underground vegetable. It is commonly called the tropical potato. Here we go. Tropical potato. Says it cannot be eaten raw. That's true. Oh they're kind of puffy like a pop chip. Ready? Hopefully it tastes good. No it doesn't taste good. I don't taste like pepper. I think something. I thought I would like it but I think it's the black pepper. No. I don't like those. That's a weird taste. Yeah I said no. No. Okay. So the next thing Howard's going to open are these. Like banana, chocolate, weavers. Those things are strong. They're not good. They're not good. It's a chocolate banana wafer roll which. Oh there are several. The box has several of these packets in there. Individually wrapped. Banana is actually originated in Indonesia back in 8000 BCE. And they're called the golden banana. And I really don't care for bananas that much either. Oh it broke. Anyway it's one of these little things here with some chocolate stuff in the middle. It looks like the same kind of thing you see all the time right? Yeah. That chocolate in there is super dark though. It's not very appealing. It smells just like banana. Oh yeah it does. It's not the bigger piece. Cheers. I think banana. It is very banana-y. What about? If you like bananas you would like it but I don't care for bananas so. Alright what's left? And I don't know if we mentioned but those coconut bars. We got two of those in there. And two of these too. Yeah I forgot to mention that. Alright of course they always have a young bag full of candy and stuff. It probably won't go through them. Yeah because there's so many different varieties of candy and they're hard candy and so I know you guys don't want to sit there and watch us eat hard candy. So we're going to skip over that but Howard will show you what's kind of in there. What's some of the stuff in the bag? Yeah there's tons and tons of stuff. Lots of different ones. Another thing that is in the box. Oh this looks weird. So it's called yuppie noodles. They are sour gummies and they said that. Let me see here. It's a common noodle dish. It looks like an egg there. Can you take it out? I think it slides out. I think it slides out. It says it's a common noodle dish. It's thin noodles, pan fried and garlic and onions and then chopped with a fried egg. So that's what that's supposed to be like. It's interesting looking. But it's gummies. It's all candy. Yes it's a savory. Actually you said this one is savory. I probably won't like it. Yeah. And the last thing is what is that? Yuppie fruit flavor. It looks like gummy bear stuff. Oh here it is. Actually those are milk gummies. You want to try one real quick? Sure. Fruity creamy cow shaped gummies. Cow shaped? Yes. Oh they have different colors and everything. Yeah. Oh a milk gummy. Oh oh oh. I got two cows here. Yes they are all cow shaped.  Yellow cow. Got a red cow. Oops I doubt it. Red cow and an orange cow. Moo moo. What color cow do you like? I like the grape one. That's grape? That's grape. Oh I didn't know it was. Not black. It's a little grape cow. Oh I didn't know. Alright I'll have, I guess I'll have the orange cow. Okay cheers. They're good. They're no, is it hair bro? That's the kind I like. They're very soft. I don't taste any milky. Mine didn't taste like orange. What did yours taste like? Grape? I think so. You have to fake it. What did yours taste like? I don't know. I'll try another color off camera. But that's it. That's our entire box. We hope you guys enjoyed this unboxing. If you haven't subscribed to our channel we'd love to have you and see you guys next time. Bye.