Tako, počekaj smo pričočati. To je najbolj, da je najbolj by Leonardo Rastelli, kaj je pričočiti o karalalgebra programu za 4-dimensionalne, superkonformalne teorijs. Tako, počekaj. Vseč nekaj, da je 4-dimensionalne, konformalne teorijs, nekaj, cft, in 2-dimensionalne karalgebra. Or, as mathematicians would prefer to call them vertex operator algebras, I will use the two names interchangeably. So, it's a by now rather rich and complicated story and it will be impossible for me to completely do adjusting for lectures. And although I was told that this is supposed to be a very advanced audience, I didn't quite, perhaps we should wait, people are still coming in. I didn't quite had the courage to assume that you already know everything about n equal to two field theories. And so I will start today with a rather pedagogic and elementary overview of n equal to two super conformal field theories in four dimensions, partly as a way of motivation. So, our work, so I can say it in a slogan, so we have this rich landscape of four dimensional theories with n equal to two super symmetry, it's a growing list. It's in a way much richer than the maximum super symmetric case, which is n equals to four, which is more constrained, but still has sufficient structure to allow remarkable analytic progress. And much progress has been done, but what we will describe is a particular sub-sector of these complicated theories, which turns out to be isomorphic to something very tractable. So, you're familiar with chiral algebras, chiral algebras are the purely holomorphic left moving sector of a two dimensional conformal field theory, so meromorph is very powerful. And this correspondence has many uses, as always often is the case with this kind of correspondence or dualities, the error both is powerful both ways. We can use the fact that the bottom line is tractable and has infinite dimensional amount of symmetry to find interesting results, interesting result for dimensional theories. And we can use physical intuition about four dimensional theory in the other direction to formulate mathematical results about two dimensional chiral algebras, which you can then hand to mathematicians and they will prove theorems. And perhaps the most ambitious goal, which really is my current focus and this will be, ambitiously, the punchline of these lectures is to use this correspondence as an organizing principle for the whole landscape of, so the idea is to use this as an organizing principle and perhaps even as the beginning of a classification program. Ok, so, this is all great, but I think it would be a little premature for me to jump into the structure without any motivation. As a way of motivation, I will describe today in a really lightening way the basic structure of n-equal 2-2 theories in four dimensions and I will do it from, so the outline for today will be a review of n-equal 2-2 super conformal field theories and optimistically I will start with basic stuff, such as we will start with baby steps, familiar vanilla type of n-equal 2-2 theories, I have a Lagrangian formulation and then I will promote a more abstract viewpoint based on super conformal representation theory and I will tell you how the algebra of local operators is useful, that will be my basic organizing principle and try to connect that also with the geometry of vacuum branches. Ok, so that's a little ambitious, but we need to start somewhere. Ok, so, I assume the basis of supersymmetry, I just want to remind you of the basic elements, so there are two types of supersymmetric multiplets that we will consider, we will consider the n-equal 2-2 vector multiplet, which in familiar component language consists of complex scalar phi and two gauginos lambdas, so phi is a complex scalar, so I will also use the notation lambda i alpha where i goes from 1 to 2, so, just to, ok, so, again, I need to assume you know the basics of supersymmetry, let me write the supersymmetry algebra in this. So, we have two copies of a Susie algebra, so the index i is an SU2R index, so this is the art symmetry of the theory, the full art symmetry of the theory is really a U2, which we will decompose into an SU2 times a U1R, and my notation throughout these lectures will be very consistent, I will always denote with capital R the non-habilian art symmetry and with small R the abelian one, and also by abuser notation I will often denote by R the carton of SU2R and by little R the generator of U1R, and those of you who are familiar with n-equal 1 supersymmetry in terms of n-equal 1 multiplets, we can decompose n-equal 2 vector multiplets into n-equal 1 vector and into n-equal 1 chiral super fields. Ok, so, it's clear that if you have not seen this before, this is going to be meaningless, so you are just doing it as a way of recap notation and also because I will need some of this notation to write down a few examples. So, this is the vector multiplet contains the gauge fields, which I am writing here by spinorial notation, and so necessarily by the general principle of quantum field theory the moment you have a massless spin one object you must have gauge symmetry, this is a famous result from the old days, and so necessarily the n-equal 2 vector multiplet has in this app now written down, it transforms in the a joint representation of some group G, which is going to be the gauge group. The other multiplet I am going to write is going to, well, let me do it in a slightly more precise way than it is often done, I am going to write the n-equal 2 to half hypermultiplet, which will be a, let me try to be precise, it's going to be again a complex scalar q vile fermia, I am going to write psi alpha, and cpt conjugation does not leave this multiplet invariant, there is a whole discussion that I need to shortcut a bit, but if you look at the representations of one particle states, which hopefully you are familiar with that story where you construct, you know, you go to the, you look at massless representations, you construct this cliffer vacuum and combine different representations in such a way that they are cpt self conjugate, it almost looks like this one is cpt self conjugate, but that's not quite the case, and the reason for it is that the, necessarily we will find a pseudo real representation of SU2R, the fundamental representation of SU2R, so in order for this object to make sense, really one must consider a whole pseudo real representation under some other group, let me call it G, it doesn't have to be necessarily the same as the gauge group, there has to be some additional, so this is forces, this guy to be in a pseudo real representation, in some pseudo real representation are pseudo real of G tilde and then the whole thing can be made, cpt self conjugate. Ok, so for those of you who are slightly puzzled by this, so the more, the most familiar case of this situation is one where we consider a full hyper, which will consist of two half hyper, a half hyper you will have recognized, it's really the same thing as any whole one, kind of super filled, and we are going to consider a full hyper where we consider this in representation R and this in representation R star, and then in the R times R star there is a natural pseudo real, but the most general situation is the one where I align there, where we are not necessarily assuming that we have two different copies in two complex conjugate representation, we may have a situation where we have a honest pseudo real representation, which cannot be written as a direct sum of two complex conjugate representations. Ok, so, with this data you can now start constructing Lagrangians, and again, I'm not going to really be able to do, I mean truth be told, what people usually do is write even n equal to Lagrangian n equal to one super space, and then the covariant ties with respect to the non abelian arts symmetry, that's still the most efficient way to do it, because n equal to two super space is a bit cumbersome. There's a nice simple construction, so this is a side note, n equal to two super space is naturally and easy for the n equal to two vector, but it's a bit hard for the n equal to two hyper or half hyper, because it requires an infinite number of auxiliary fields. For the vector there's a nice simple way of doing it that I just want to mention briefly. You introduce Grasman coordinates theta i alpha, where i again is one to two, and alpha is my index, is my vile index, and then you write down the full super field, again by abuser notation, you write down a full chiral super field in this n equal to two super space, so it depends only on the thesis and not on the theta bars, and the expansion of this guy will contain the gauginos that we saw earlier, and then the theta square component you will find the gauge field, and then there will also be a piece that contains a triplet, an s2 triplet of auxiliary fields. I mentioned this briefly because it will allow me to save a little bit of time later. In the more familiar n equal to one notation, this triplet of auxiliary fields will be written, so in n equal to one notation be even by the familiar f, f bar, and the auxiliary fields of the chiral super field, and of the n equal to one vector super field. Yes, of course, I'm sorry. I was just a typo, sorry. Ok, so, again, I'm sure cutting this whole discussion, but let me just assert the following that if we, at the classical level, at the level of writing down classical Lagrangians, if we insist that they are classically scaling variant, then if you fix the matter content, which means you fix the gauge group, and you fix the representation under which the half hyper transform, then the Lagrangian is unique up to choice of the gauge coupling. Ok, so, the basic data of n n equal to two Lagrangian are choice of g, which a priori can be a product, where each gi is a simple vector, or at this classical level it could also be a u1, and then a choice of a representation r for g, which by the quick, not really argument, but the quick assertion I had earlier, must be should be real. Ok. So, the simplest, and just to belabor the point I made earlier, that the simplest and cheapest way to construct a shoulderier representation of g is to take r to be the direct sum of, let's call them, well, let's call them r prime of two representations r prime in its complex condition r prime star, but more general possibilities are allowed. And so, these are the discrete data, and then it turns out that n equal to two supersymmetry fixes the Lagrangian uniquely. For the vector multiple, that's very easy to believe, because you just take the familiar Lagrangian for n equal one vector multiple, it's in your covariantize with respect to SU2, remember we had two lambdas, lambda one and lambda two, you covariantize the n equal to one Lagrangian, you get the right answer. In other way of writing the Lagrangian for the vector multiple is to write it using this simple superspace, which you can do easily. The construction of the full Lagrangian including matter is a little bit more involved, but a cheap way of saying what you need to do, you do minimal coupling. OK, so you have the familiar story in where you want to couple the gauge field minimally to the nether current under the symmetry, and you want to write down an n equal to two SUSE version of minimal coupling. And that can be done, although the details in superspace are a little bit involved, so I'm not gonna write it there, write it down, but what you are doing in simple terms, you are, and we will come back to that in a minute, because it will, right now I'm unfortunately painful, it's slowly just a view in basic Lagrangian territory, and I will graduate soon to a more abstract presentation. The way to do it is to recognize that the conserved current really belongs to a full super field, so we're gonna view the conserved current j mu, or in the notation I had earlier, j alpha alpha dot, as a member of a super field, and this super field, again, you take my word and later we will do this in a little bit more detail, as top component, or according to how you count, bottom component, a element, which has dimension two, and it's an SU2R triplet, and then there will be some fermions, which I'm not writing down, and in the next level you will find, when you add with two supercharges, you will find the current and also a complex scalar. So in n equal to 2 theory you write j alpha alpha dot as the action of two supercharges, two Poincaré supercharging, acting on this bottom component of the super field, which for reasons that come from geometry and that perhaps will become mere to some of you and later on we will quickly review what is also known as the moment map operator. So once you have recognized that the current you want to count minimally to the gauge field has this nice n equal to covalentization, what you basically want to write down is some souped up version of this where you couple the full n equal to 2 vector to this full fledge, let's call it mu, to conserve current superfield, and this fixes uniquely the coupling of the matter to the gauge field. Under which assumption, so whether on the assumption that the theory is classically scale invariant, so I'm not allowing for mass terms, and as always is the case, each simple factor of the gauge group comes with the choice of complexified gauge coupling in the standard. So to summarize, to write down a classically scale invariant n equal to 2 Lagrangian, you choose a product gauge group, a should be a representation of this product gauge group, and for each simple factor, a priori one factor, you choose a complex parameter tau, which lives in the complex upper half plane, because the coupling is assumed to be, of course, real. Now, as we graduate to quantum field theory, various choices are possible, and it is certainly allowed to consider general, much more general type of structures if you are interested in viewing these Lagrangians as low energy effect field theories, but my focus here right now in writing down UV-complete models that make sense as you stipulate them to short distance. And so, you will recall that you won famously as a positive beta function, and so it's not well defined in the UV, so we will insist. So in writing n equal to 2 quantum super conformal field theories, we will dismiss the U1s, and so then these are the data, the same discrete data as before, and then a set of continuous gauge couplings. Now, it turns out that nonperturbative dualities will carve out generically a smaller subset of these complexified gauge couplings because there will be discrete identification in this space, so that theories related by the discrete identification are in fact physically equivalent. So the complexified gauge couplings a priori should be modded out by some duality group. Let me give you an example. N equal to 4 superion mills is a special case of N equal to 2 theory, and there we have a single non-abelian gauge group G, and we take R to be the a giant representation of G. We have a single complexified gauge coupling, but famously there is a SL2z invariance that restricts the physically distinct values of tau to the fundamental domain of SL2z. In that case, duality group is SL2z. Since I need to pace myself, I want a quick raise of hand. Who among you already knew everything about this? It's actually not... It's less than half, so I'm glad I'm not completely wasting your time. OK, so the next step if you are interested in conformal... OK, so I already made an assumption that I want to exclude the U1 factors because they lead to inconsistency in the FIUV and I'm trying to write down something which is a fundamental Lagrangian description, not some Lagrangian description. Of course, those of you who are familiar would say it's a Beewittian theory. You know that there's, of course, very much beautiful use of U1 gauge fields. If you view your Lagrangian as in a derivative expansion, as in a Lagrangian effective action, and then, of course, a Lagrangian is a lot more complicated than what I wrote down. I should have also emphasized. When I said N equal to 2 super similarly fixed Lagrangian uniquely, it fixes the... There are various ways of saying this. It fixes the renormalizable Lagrangian uniquely, or if you assume that you have classical scaling variance, of course, all the higher irrelevant operators are forbidden, and so you have a unique structure. But if you don't make this assumption, then you can have a complicated derivative expansion and then N equal to super similarly only relate some terms, but it does not fix the Lagrangian uniquely. If you are now interested in promoting the story to a full quantum story, we need to make sure that the scaling variance is preserved. Remember, our goal is conformal field theories. We are in particular scaling variance, so we need to make sure that the beta function is zero, and there is a beautiful implication that happens here. It is sufficient to check the vanishing of the one loop beta function. So a quick heuristic argument for the vanishing of the higher perturbative terms comes from holomorfi. You know that N equal to one theories have a holomorfi scheme where only the running is one loop. That holomorfi scheme, however, introduces wave function normalizations for the terms that appear in the Keter potential, and so it's not the usual physical scheme where the Kira superfields are chronically normalized. But thankfully N equal to two supersymmetry relates that piece of the Lagrangian with the better piece of the Lagrangian, so you know that that is actually the physical scheme in which simultaneous you can have holomorphic and absence of the wave function normalization, and then holomorphic, remember tau was this combination for pi i over g square plus theta over 2 pi, holomorphic allows you to quickly conclude that you have loop correction beyond one loop because they would have to depend on the imaginary part of tau, and so they would not be holomorphic. So we simply need to impose the vanishing of the one loop beta function, which, of course, for the u1 factors, that could never be possible, and that's why we discarded them. And then for each simple factor g i in my product gauge group, so let me not put the index i to avoid cluttering, there will be a negative contribution that comes from the better multiplet. A-check is the dual-coxater number of the particular... I'm writing the full gauge group as a product, and then this is the dual-coxater number of the particular factor g i for each i I'm doing this, and then you get a contribution from the half-hypers, which turns out to be the index of the representation heart. This is the notation, which is proper for half. So, for example, if I take g to be SUn, the number is n, and I'm using conventions where the index of the fundamental representation is one-half, and the index of the adjoint representation is n. And so now we can check familiar examples of n equal to two Lagrangian field theories. So, I wrote that formula for half-hypers, and I'm sorry for being a little bit pedantic about half-hypers, but I'll tell you a little secret. So people claim to have classified all Lagrangian n equal to superconform of field theories, and it turns out they had made a little mistake. And this is the last one, because I had not been careful about this basis of half-hypers, so it's actually something that one should always keep in mind. So I wrote this for half-hypers, of course for full-hypers, which is the simplest situation, then we would just put it twice there, obviously. And so if I take g equal SUn, there are two familiar ways in which you can satisfy this condition. You can either have nf equal to n fundamental representation, you can just check that this works out, minus two little n plus two times two n times one-half gives you zero, or you could have one adjoint, and this is what we would call n equal to two superqcd, and this is the case in which, in fact, the super symmetry enhances to the full n equals to four. OK. So another little exercise you can do is to convince yourself, which can be done by specific calculation, that the one loop coefficient of the beta function also controls the anomaly of the U1r. OK. So remember, classically we have this SU2r times U1r, if I don't break the classical conformal invariant by my terms, this is the true symmetry of the classical Lagrangian, and this is manifestly preserved by quantum effects, but the U1r is broken by the anomaly, but the anomaly is actually proportional to the beta function. This is something you can quickly do if you recall that under a chiral rotation the measure for vile fermions transforms under something which is this times k, where k is the instanton. And so if you look back at the matter content of the n equals to vector multiplied, there were two gaugenas, who are careful about little arc symmetries. Well, I didn't say that, but let me say that. So remember we had this, we are going to assign r equal minus one, r equal minus a half, and r equal to zero, whereas for the half hyper, this is our assignment, and with these assignments you can convince yourself that the anomaly precisely cancels when the beta function is here. So in n equals to two theory with vanishing one loop beta function, first of all the beta function vanishes to all orders, so the theory is truly scaling variant, you have an exact SU2r times U1r symmetry, but then let me assert without further ado that so we have scaling variance, d, we have arc symmetry SU2r times U1r, and then of course we have Poincare, and as is familiar, the scaling variance and the Poincare invariance will enhance to the conformal algebra, so I should perhaps write it here, the Poincare symmetry, so we have Lorentz generators, and we have momenta, and these will enhance to the full SU4,2 or SU2 slash 2 conformal algebra, and in fact we have super symmetry, okay, so let me just write it, and then I will comment on it, there will be an enhancement of the superalgebra in the full-fledged superconformal algebra, which almost each of the same as I make would require a separate lecture, so I need to take it for granted that you know what the conformal algebra is, so the additional generators that you find here are the momenta, now come with partners, which are the special conformal generators in spacetime dimension d, special conformal generators, and then if you have Poincare supercharges, they come accompanied by their conformal analogs, which are conventionally denoted by s, and furthermore the full structure will close on the right hand side of the commutator of q and s, you will also find generators of the full art symmetry so that the whole superalgebra is, in fact, s2,2 slash 2, okay, I'm going to discuss the structure superalgebra in a little bit more in detail in a minute, but that's the story, so questions about this. Okay, I need to be ruthless, because otherwise I'm never gonna get to the heart of the matter. So what are the features that I'd like to emphasize? First of all, you can now solve a fun combinatorial hazard size, of which many aspects were known a long time ago, but there was a nice paper by Tashi Kava and collaborator who did a systematic analysis missing one example, where you can take this discrete data, which is the choice of the product gauge group and the choice of the pseudo-rear representation of the gauge group and this condition that the one-lubita function must vanish and classify all possibilities for n equals to superconformal Lagrangians.  One thing you can do just for the fun of it is to assume that the gauge group is a product of SUN factors and further assume that the matter comes into bifundamental representation of any two of these SUN gauge groups, and then you will probably have encountered this fun quiver notation where we have, sorry, I missed your lecture, perhaps you had quivers, where we have a little blob with an N1 here and then we have an N2 here and this means that we have an SUN1 and this means that we have an SUN2 gauge group. It's a way of encoding the structure of the gauge group and that we are connecting them by a line means that we have a full hyper in the bifundamental representation of the SUN1 times SUN2. And then the question is what kind of quiver diagrams you can draw that are conformal. And the answer turns out to be very beautiful. First of all, okay, I don't have, it's a fun hazard size to do in detail but I really don't have the time. One thing you can do, well, you can easily convince yourself that you need to ensure the vanishing of the beta function at each node. So the beta function for this node gets, remember the formula, it was minus 2hv plus 2c2r in the notations where I'm using notation for full hyper multiplets and you will remember that the SU2 of the fundamental is equal to 1hv. So from here we get for, if I focus on the contribution of the function from this gadget, I will find minus 2n plus 1hv times 2 and then I need to count how many hyper multiplets I have but I clearly have n from this side, n from this side because from the point of view of the symbol symmetry and n from the other side so I get 2n and this is happily zero. And so clearly I can't keep going except that, of course, I don't quite know what to do at the end and the simplest way to make this work is to just connect it back and write down a sort of circular river diagram with all SUn groups of equal rank. The same would be to end this story here. OK, let me call this 2n would be at the end in this way and then there are a couple of three more exotic possibilities but the statement is that if you assume that there are no flavored symmetries and if you assume that the gauge group takes a product of SUn and factors, all the possibilities are classified by drawing the affine dinking diagrams for ADE. So there's this ADE affine classification. OK, so this was a bit quick but perhaps you've seen this before. Another fun example I could do would be the... Well, let me not draw it. So this is the A k hat where k is the number of nodes. This would be the dk and then you can go to our colleague Wikipedia and check the dinking diagrams for E and... Anyway, these are all very nice examples of n equal to 2 super conformative theories in four dimensions. So this is also a little bit more elaborate where you assume we can improve our set of possibilities. We can enlarge our set of possibilities by assuming that we can also have hypermultiple which are charged so this would be a hypermultiplet which is in the bifondamental of this gauge group SUn but it also transform the mental representation of some additional symmetry group SUk which, however, is not gauged. So the standard notation is that we use circles to denote gauge groups and boxes to denote flavor groups and so you can now enlarge your set of possibilities by decorating these quivers with these kind of boxes and I will leave you with the answer and then you can have some fun trying to argue for it so if I have let me call this v if I consider a quiver of this type with... in principle now I can have I can decorate it with additional flavor symmetries of this kind then the condition that this be conformal at each node is this one where Cij is the Hartan matrix so ok, so this is just a very quick list of possibilities just impress upon you that there is a huge class of just Lagrangian theories and the once you have spent 10 seconds to be impressed by that I'm gonna graduate and tell you that this set of Lagrangian theories of which I just enumerated a few examples by drawing quivers are in fact just a tiny subset of what we now believe to be the full set of any kultutu super conformal filled theories and how do we know that? Well we know that a bit indirectly the simplest and perhaps from what I've told you so far the easiest way to get to that conclusion is to try to take the strong coupling limit of any one of these Lagrangian models and to realize that there is a duality transformation that will require the existence of another super conformal field theory that cannot be written in the language that I just described so far another way of doing this of course which is also related is by constructing more mysterious that cannot be written in this language from various decoupling limits of string theory or amp theory so the emerging picture is the following so now we are getting into the more conceptual territory where I want to eventually go for the rest of the lectures which is to try to delineate the full space of any quantum super conformal field theories and the emerging picture is the following so here we had a nice separation between what you may want to call matter which were the hyper multiplets or the half hyper multiplets and gauge fields and the continuous parameter of the theory the compensified gauge coupling were purely carried by the gauge field so I'm going to speculate that this is so the conjecture the full space of n equal to 2 d equal to 4 super conformal field theories arises by gauging of isolated super conformal field theories of which the free hyper multiplets is a simple example one can make it more precise but the idea is that you have exotic type of matter you have ordinary matter which is the hyper multiplets those we understand because you can write down a free field Lagrangian for it and then you have exotic matter which is characterized by the idea that there are no continuous parameters this parameter tau that I had earlier is from the point of view of conformal field theory is what would be called an exactly marginal deformation it's a deformation that preserves in this case the full super symmetry but in fact more to the point the full super conformal symmetry in some sense call, exotic matter a theory that has no exactly marginal deformation it's a isolated fixed point of the renormalization group and the only such theory for which we can write down a Lagrangian model are the free hyper multiplets and these other more mysterious type of matter theories should be understood as some strongly coupled isolated fixed point that we must describe more abstractly but the idea is that we can then treat as an abstract beast and introduce parameters by gauging some subalgebra of the global symmetry algebra of these theories and this is the only way in which you can get exactly marginal deformations or to say differently the picture of the space of exactly marginal couplings of a general n equal to 2 super conformal field theories looks a little bit like this where this cas point corresponds to points where the gauge couplings at least one of the gauge couplings in my private gauge group is going to zero and at this point you will decouple a piece that has no marginal deformations and this is clearly a special point Am I making sense? So there are familiar examples of this story where one point is perfectly described by Lagrangian tools you have a bunch of hyper multiplets coupled to gauge fields and then you go to some other point where you recognize that in that limit some other gauge group is becoming with the cup and what you are left with is a product of perhaps familiar stuff like hyper but also unfamiliar stuff that has no obvious Lagrangian description and the full set of theories is obtained by gluing together these elementary pieces making sure that the beta function is zero and so really one of the main goals of our abstract considerations when we got the way to this chiral algebra correspondence is to be an understanding of these strongly coupled pieces Ok, so what next? So since I mention this let me also put a little bit of more equations so remember I wrote down this abstract I wrote down this abstract the way in which I was describing the minimal coupling of the gauge field to some conserve current and you recognize that if my picture is correct I get to treat the gauge fields using a conventional type of Lagrangian but it might be that the what the gauge field coupled to is something that does not have a simple Lagrangian description nevertheless I can think of this moment multiple that contains a conserve current abstractly and so we'll be coupling the gauge field to some conserve current of my strongly coupled piece and then I can rephrase the vanishing of the beta function in this purely abstract way by declaring that my conserve so this will become a little bit more clear once we graduate to confirm a representation theory but the idea is that the strongly coupled theory may have as a certain symmetry algebra and corresponding there is a conserve current associated with the symmetry algebra and I can define the level abstractly in some normalizations that I need to be write rather quickly because I don't have time to get into all these details there's a way to normalize the currents that so a conserve current has dimension 3 and so you see that dimensionally this works and the non-abelian structure constant fix uniquely this normalization so I have then meaningful data is contained in the two point function and this is the level of my four dimensional current algebra and then in those conventions you can write down the condition for the vanishing of the data function in this more abstract way making sense this of course we reproduce the condition that I had earlier for in the case where I can think of the current as a composite field of free hyper multiplets but the more general subscondition is this one and so this is the first baby step towards this sort of more abstract view point that we want to take we want to think of this theories as define abstractly in terms of a set of local operators and their operator prowess functions and then even something as pedestrian as a vanishing of the beta function can be set in that pure lepser language ok, so how am I doing with time? ok, so ok, so this is about half of what I want to cover but I will have to be a little bit rootless next time


Hi, and how are you all today? The question says, P and Q are respectively the midpoints of side A, B and P, C of a triangle A, B, C and R is the midpoint of A, B. Show that area of P, R, Q is half of area of A, R, C. Area of R, Q, C is equal to 3 by 8 area of A, B, C and area of P, B, Q is equal to area of A, R, C. So we will be proving all these three one by one and let's have a diagram that can model this situation. Now this is a diagram which satisfies all the condition which are given to us. P and Q are the midpoints of A, B and B, C respectively. R is the midpoint of A, P. And now let us start with the first proof. First part given to us is area of P, R, Q is equal to half of area of A, R, C. This is what we need to prove over here. We will be proving it very slowly and then only you will be able to understand this proof. Now let us start with the left hand side area of P, R, Q. Now you must know one of the theorems which says or properties which says that a median of a triangle divides a triangle into two equal areas. Now we can write this here, a median of a triangle divides it into two triangles first of all of equal area. Right? Now we will be making a lot more use of this property in solving this question. Now here we have started off with area of P, R, Q. This is P, R, Q. This is the triangle that we are talking about right now. That is, let us shade it a little and we need to prove that this is half of A, R, C and A, R, C is this triangle. Right? So let us start. Now we can say that P, R, Q, if you notice, R is the midpoint of A, P. So if you join R with Q, Q, R will become the median, isn't it? So this median will divide this triangle A, Q, P into two equal parts. Let me draw a small triangle that will help you to understand it more clearly. Now this is E, P, Q. We know that R is the midpoint of A, P. So if we join R with Q, Q, R will become the median of this triangle and we can say that area of P, R, Q is half of this whole big triangle. That is area of A, P, Q. Right? As we have discussed, a median divides a triangle into two equal half. So this is half of this whole big triangle. Further. Next we can say that we have this triangle. Now I will be drawing small triangles just roughly to make your understanding more clearer. Now we know that P is the midpoint of A, B. So if you join P with Q, it will become the median again and it will divide it into two equal half. So that means this area is equal to this area. So we can say that A, P, Q. A, P, Q that we have discussed in our first part is equal to P, B, Q. Right? So here we can write in place of A, P, Q, P, B, Q. Because this median is dividing it into two equal halves and the area of this triangle is equal to this triangle. So in place of this triangle we can write this triangle. Similarly, we know that if you notice it from above figure only, I am drawing this figure from above figures only. But since it is having a lot more triangles, I am taking those triangles which I am needing in every step. Now we have this triangle P, B, C and Q is the midpoint of B, C. If we join P, Q, if you notice P, Q, it is the median of triangle A, B, C. Now A, P, B, Q, this triangle can be written as it is half of P, B, C. Right? So we can write that it is half of area of P, B, C. Further, now P, B, C, P, B, C is equal to A, P, C. Let me draw a diagram to make you. Now this is a triangle, the initial triangle A, B, C which we were having and we know that P is the midpoint of A, B. So C, P will be the median. Now we can say that P, B, C is equal to A, P, C. The areas are equal. So in place of P, B, C in the above step, we can write down P, C. Right? Further, now A, P, C, this triangle, this is A, P, C. R is the midpoint and on joining C with R, this will become the median and this areas are equal. So in place of A, P, C, I can say that this is twice of A, R, C. Since it's a question, I want A, R, C. That is why I am moving from here to here in order to get A, R, C anywhere in the right hand side. So I can write it that A, P, C which was in the above step can be written as it is twice of area of A, R, C because it's the double of any of these parts. It can be twice of R, P, C also and A, R, C also. But we are taking A, R, C because in the right hand side of the proof, I want A, R, C. Now these two will get cancelled out and we are left with half of area of A, R, C which is equal to R, RHS. So here LHS is equal to RHS and hence we have proved the first part. Now let us start with the second part. Here we need to prove that area of RQC is equal to 3 by 8 area of A, B, C. Or we can write it that 8 times area of RQC is equal to 3 times area of A, B, C. This 8 is be taken on the left hand side. Now let us start with the left hand side. That is 8 times area of RQC. Now we can write area of RQC, RQC as 1 by 2 area of RBC. Let me draw a rough figure that will make it more clearer. Here we have RBC, a triangle. Q is the median. RQ will be the median. So this whole triangle that is RQC is half of this big triangle, isn't it? So I can write that this area of RQC is half of this whole big triangle which is RBC. On simplifying I have now here 4 times area of RBC. Further RBC can also be written as if you see RBC. Let me draw it and here I have B, this is RBC. P is not the midpoint. Now if you carefully see that area of RBC can be written as area of RPC, this plus area of this triangle that is RP or PB, right? This whole triangle is the sum of these two areas of the triangle. Now I can write RPC as RPC as half of this big triangle, half of area of APC and PVC, this is PBC. Can be written as this is equal to APC. So in place of PVC I can write APC that are equal. Now if you take APC common and add 1 by 2 in 1 as it is 1 over here, we have 3 by 2 area of APC. On simplifying we have 6 times area of APC. Now if you observe we have to have ABC. So APC can be written as this is half of the portion of this big triangle. So I can write that 6 times area of APC can be written as that this is half of ABC. On simplifying we have 3 times ABC which is our RHS and hence we have proved the second part. Now starting off with the third part we need to prove that area of P PQ is equal to area of ARC. Now here let us start with our right hand side. You can start with any of the sides. Area of ARC can be easily written as half of area of PCA. Let us have a diagram. APC R is the midpoint therefore CR will be the median. So ARC this triangle can be written as half of this big triangle that is APC or PCA you can name it as anything. So this is half of this triangle whose name is PCA. Now PCA can be written as ABC. Can you name it Y? Right exactly. I know that ABC is a triangle where P is here the midpoint. So PCA this triangle can be written as equal to PBC as they both are equal in area. So I can write any for I can write PCA or PBC they both are equal areas further. Now this PBC is twice the area of P B Q. How? I have this triangle PBC and Q is the midpoint. Now here if you see PBC that is this big triangle can be written as twice of this triangle as twice of this triangle but I want PBQ that is why I have written twice of PBQ on simplifying it becomes equal to area of PBQ and that is the right hand side that we were waiting for and hence we have proved the third part also and this ends the session. I hope you enjoyed just start from any of the side and take care that you need to reach on the other side and just focus on the area of the triangle that you need. Bye for now.


The last talk of the session is Cryptography with Temperable and Leakie Memory by El-Tauman-Kalai, Bavana Kanakursi and Amit Sakhai, and Bavana will give the talk. Thanks, Evgeny. So you've had enough time to stare at the title slide, so I'm not going to repeat the names again. But before I start, a big thanks to all the speakers of the session for setting up so many of the concepts that I'm going to use. I'm just going to jump right into the talk. So as we've seen in these sessions, motivated by powerful physical attacks, cryptographers have done a lot of research in building primitives that are resilient to leakage. So a lot of great research has gone on to this. And in particular, by now we have some amazing results in this area. We know how to build cryptographic schemes that are secure against continued leakage. Basically the adversary gets leakage about the secret key over and over again. The amount of leakers that she gets could be unbounded. It's not bounded in terms of the length of the secret key. And this was shown to be true in two recent papers that appeared last Fox, the first by Dodis Harlembe, Lopez-Alton-Wicks, and the second by Brackersky-Kalai-Katz and Vaikunthanathan. So great results. But physical attacks are not just restricted to leakage attacks. They could also tamper with the memory. And this is something that needs to be addressed. And as we've seen, there's a lot of work which shows that this could potentially be even more dangerous than just dealing with leakage. Okay, so that's going to be our focus of the talk. So let's see what's been done in the area of tamper-resilient cryptography. So surprisingly in this area, there's been fewer results. The work of Janaro, Lissanskaya, Malkin, Mikali and Rabin, they achieve very strong guarantees. They show you how you can actually deal with arbitrary tampering functions. But they rely on some user-modifiable memory, user-specific memory, that's actually non-tamperable. So think of it as the user's public key being stored on non-tamperable memory. Then there's the work of Ishai Prabhakaran, Sahay and Wagner, where they consider a much stronger model, where the adversary tampers not just with the memory, but with all parts of the computation. The disadvantage here is that they consider only tampering functions that are restricted, that set or reset bits. Then there's work in the area of related key attacks, for example, by Belare and Kono and Applebaum, Harini and Ishai, and also work in the area of non-malable codes by Dumbosky, Pyrschek and Wix. But these works, again, while they're related, they consider only restricted tampering functions. And that's the main challenge, that's what we'd like to address. In particular, our goals are as follows. We want to build leakage and tamper resilient schemes, so we want to handle both leakage and tampering, that always satisfy the following conditions. Any memory that's user-modifiable needs to be tamperable. We need to aloft the adversary to tamper with it, if the memory contains any information that's specific to the user. For instance, the user's public key and the private key, they have to be stored on the user-modifiable memory because it's specific to each user. So that's something we want to aloft. Also, we don't want to consider restricted tampering and leakage functions. We want to aloft the adversary to do any arbitrary tampering, any arbitrary leakage. And the good news is that we actually achieve this. But the flip side is that this is small caveat. We have to assume non-tamperable public parameters. So think of this as the CRS. But it would have been awesome to actually get rid of this assumption, but unfortunately we're not able to, but not all is lost because the important point is that these public parameters do not depend on the user's information, user's secret keys in any which way. So you could think of the manufacturer actually hard-viring these into the circuit itself, into the user's device itself, so they don't actually consider, you know, contain any information that's specific to the user's keys. Okay, so they're completely independent. We also rely on a source of true randomness which again seems to be inherently necessary. Okay. So this brings us to our results. In our first result, we present a general transformation that converts any scheme that's resilient to bounded leakage into one that's also resilient to continual tampering. So what do I mean by bounded leakage? You already heard it in the previous talk, but let me just give you a quick overview. So in the bounded leakage model, the adversary gets a fixed amount of leakage about the secret key. For instance, 90% of the secret key could be leaked and that's it. That's the only leakage the adversary's allowed. So we want to take a scheme that's actually secure in this model and convert it into a scheme that's resilient to continual tampering. Basically, the adversary will tamper with the secret key, how many of our times she pleases and it should still be secure. And that's what we get. Our transformation is based on general primitives but the specific instantiation that we have uses fully homomorphic encryptions and NIZ case. In our second result, we construct encryption and signature schemes that are resilient to continual leakage and tampering and this is based on linear assumptions over bilinear groups. So the second result is what we view as our main result and most of our paper has gone towards proving the second result but due to time constraints, most of the stock will go towards showing you result one. Okay, so that's what we're going to focus on. So here's the model. We want to build a signature scheme in the continual tampering model. So the challenger is going to pick his keys and send the public key across to the adversary. The adversary gets to specify arbitrary tampering functions. The only constraint is that it has to be poly time but other than that, no other constraints on the tampering function. Okay, the challenger, you know, deletes the old key and replaces it by T of SK and then the adversary gets to see signatures on the stampered secret key. Okay, and this process continues and finally to succeed, the adversary's goal is to succeed in a regular forgery attack. She needs to come up with a forgery that will verify with respect to the original verification, original public key. Okay, so that's the game. It's easy to see that this is actually impossible to achieve. Why is that? The adversary could just tamper with the secret key bit by bit and then simply use her signature queries to learn the entire secret key. So what's the adversary going to do? She's going to set the first bit to zero, sign a random message, see if the signature scheme is signing correctly. If it's not, she knows that the first bit is one. So she's going to do this bit by bit and learn the entire secret key. So because of this, we need to assume that the circuit self-destructs. Okay, so there's something that's going to trigger the circuit to self-destruct and it blows up. But what I mean is that the memory gets erased. And this has already been used in prior works on tamper proof crypto. Okay, and I'll tell you about the conditions under which it's going to sort of self-destruct in the next slide. Okay, but this is the model that we consider. Okay, so before we build this, I need to introduce non-interactive zero-knowledge proofs of knowledge. Most of you probably are already familiar with this, but just to make sure we're all on the same page. NIZK proofs have a prover and a verifier that share a CRS. And the prover's goal is to prove that some statement X is in a language L. Okay, that means that the prover knows the witness W. And because it's non-interactive, she's going to send exactly one message computed that she computes using the statement, the witness and the CRS. And the verifier is going to be able to use that to verify. So we need all the standard guarantees. Like it has to be zero-knowledge. Basically, it shouldn't tell you anything about the witness. You need it to be correct and so on. But in addition, we also need a few additional properties. We want our proof system to be simulation sound. What does this mean? Simulation soundness means that even if an adversary gets to see false statements, proofs of false statements, the adversary can still not compute a proof for a false statement, right? So that's simulation soundness. And a proof of knowledge essentially says that if the adversary actually comes up with a valid proof, then the simulator can extract a witness out of it. And finally, we'll also need our proof to be short, meaning that the length of the proof should depend only on the length of the witness. It'll depend polynomially on the length of the witness. And we'll see why, where all these are used in a bit. Okay, so this is our transformation. What do we start with? We have a scheme F that's resilient to leakage. When I say leakage, I mean bounded leakage for the next few slides. And what would have been nice is to get a completely general transformation, but it's not fully general. In that, we assume a specific property about the generation algorithm for the signature scheme. So the secret key is going to be chosen uniformly at random from some space. And the public key is efficiently generated, computable given the secret key. This property already holds for several bounded leakage resilient schemes. Okay, and we're gonna use S to build S prime, which is going to be tamper resilient. So the main crucial difference between S and S prime, the change that we're going to make to S is in the generation algorithm. So where before we had the secret key to be chosen uniformly at random, now it's going to be the output of a PRG. Okay, so SK is going to be PRG of R. And in addition, it's going to have one more component, namely a Nizik proof. So the entire secret key is going to consist of the output of the PRG and a Nizik proof, where the proof is of the pseudo randomness of SK. Okay, and as I said before, we'll need it to be short, simulation sound, a proof of knowledge, and so on. Okay. And the signing algorithm is similar to the signing algorithm of the leakage resilient scheme, except that before it issues signatures, it's first going to verify that the secret key is in a valid state. And if it's not valid, it's going to self destruct. Also, there are some public parameters. The Nizik, I haven't told you what the public key is, but that should be clear on the next slide. The Nizik CRS becomes a part of the public parameters. Okay, so this is our transformation. And this is the informal theorem that we get. If the original scheme that you start off with can tolerate at least size of R plus size of pi bits of leakage, then the scheme that we built out of it is going to be resilient to continual tampering, where R here is the seed of the PRG and pi is the Nizik proof of pseudo randomness. Okay, why is this secure? Okay, so what we're going to show is that it's a standard reduction. So if there is an adversary that's going to, a tampering adversary that can tamper and leak, then we'll build a leakage adversary that can leak and then break the security of the leakage resilient scheme. So we have the leakage challenger C, the leakage adversary B, and he's going to use the tampering adversary A to help him out. So the leakage challenger is going to pick SK and PK and generate his secret key and public key, send the public key across. But it's important to note here that the secret key now is no longer the output of a PRG. He's going to generate it uniformly at random because that's the secret key for the scheme that we're trying to break. The leakage adversary is going to generate on his own a CRS with the trapdoor for the Nizik proof that he's going to come up with. And he's going to send across PK and CRS to the tampering adversary because that's what he expects to see. Okay, so now the tampering adversary is going to ask two types of queries. He's going to ask for tampering queries. He's going to make signature queries. We'll put the tampering queries on hold and see how to handle signature queries. So let's assume nothing has been tampered with so far. So he's going to send across a query saying, sign this message. And it's easy to see that if no tampering has taken place, then both SIG and SIGPRIME, where SIG is the original leakage resilient signature scheme and SIGPRIME is the tampered resilient signature scheme that actually equivalent, right? So this guy's life is easy, B's life is easy. He's just going to forward the query, get back the signature and actually smart and just send it back. So he doesn't need to put in any effort. Okay, now what happens if he issues a tampering query? The only thing the leakage adversary can do, the only thing that access that he has is access to a leakage article. And that's what he's going to use. So A expects the tampering query T to be applied on the keys in the memory, right? But as far as he's concerned, the key consists of a secret key and an NIZK-proofed pi and of course the public key. So, and B is going to ask for a leakage query, but now this leakage query is going to be applied on SK and not on SK, pi. So B needs to help out C and somehow help him get pi. So what B is going to do is to build a leakage circuit by hardwiring the CRS and the trapdoor and the leakage circuit is going to do as follows. First, he's going to compute a proof pi, a simulated proof of the statement SK is pseudo random, right? This is a false statement because SK is chosen to be uniform randomness, but because we have simulation sounders, we can actually give a simulated proof and we're still in good shape. And he's going to come up with a proof and then now he has everything that he can apply the tampering function on. So he's going to apply the tampering function on SK, on pi and on PK and he's going to get back SK star, pi star and PK star. And now if the proof is valid, which it has to be because otherwise the circuit is going to blow up, the memory is going to be erased. If the proof is valid, then we know that the adversary could not have come up with a false proof. So when A sent a tampering query, it had to be that SK star is actually the output of a PRG because A doesn't know how to actually come up with a false proof. And we know because of this proof of knowledge property that we can actually extract R star in this situation. We can extract the C to the PRG. So essentially the leakage algorithm is going to extract R, R star from SK star, pi star and using the CRS in the chapter. And he's going to send R star and pi star, basically the C to the PRG and the proof for the NICK. And now the thing to observe is that once B gets this, he's got everything that he needs to simulate rest of A's queries because he can use R star and pi star to get the current state of the secret key which is SK star and pi star. So he gets the current state of the secret key entirely. And now she can just simulate the rest of A's views completely on her own. And it's because of this leakage that we give, leakage of the seed and the NICK proof that we actually need our original leakage resilient scheme to tolerate at least that many bits of leakage. Our scheme can also be extended to quite easily actually. It can be shown to be leakage resilient as well. It tolerates a certain amount of leakage. But since that's not the main focus, I'm not going to talk about that. Okay, but this scheme still satisfies only, is still secure only in the bounded leakage model. The adversary still gets only a bounded amount of leakage about the secret key. But the main question that we want to ask is, how do you actually secure against tampering and continual memory leakage? So that's our second result. I'm not going to have time to go into the details, but let me just try to give you a flavor of the result. Okay, so in the continual tampering and the continual memory leakage model, the adverse, the challenger is going to pick a secret key and a public key. And the adversary is going to get, you know, adaptively she can specify her leakage functions and get a bounded amount of leakage in any time period. And then she gets to specify a tampering function just as before. And she gets signatures. Okay, and at the end of the time period, the challenger is going to run a refresh procedure. He's going to run an update procedure. And the idea of the update process is to make sure that, even though the adversary has learned information about the secret key in the previous time period, when you refresh, it's going to be useless for the adversary, okay? So the update process is crucial. And in our case, it's also important to note that the update process is actually being applied not on the original secret key, but on the tampered secret key. So the adversary gets to specify T completely on her own. It could be an arbitrary, any arbitrary function. And still we somehow want to guarantee security of this update process. Okay, and once the update is done, there's going to be more leakage signing and tampering queries. And yeah, and I'd like to specify that this is the cartonal memory leakage model because even though in one time period, we're actually allowing the adversary only to get a bound amount of leakage in the entire lifetime of the secret key. Once all the updates are done, it's not restricted depending on the length of the secret key. So she can get unbound amount of leakage. And finally, to succeed, she's going to output a forgery. Now, the starting point for our work was the continual memory leakage scheme of BKKV. So BKKV essentially have a scheme that's secured in this model, except that they don't consider the tampering function. So there's no tampering in their case. And our hope was to actually show that the BKKV scheme itself would be secure in the model where tampering is also included. But the main challenge there was the updates were no longer secure because the adversary could choose the tampering function on his own. Since he had full control, there was no way, we couldn't get their scheme and show that it was actually secure to do updates even with those tampered secret keys. So that was the main challenge. So we needed a different way of doing updates. And this is a scheme, it doesn't tell you much. But then our next step was to see if the proof of BKKV itself, we could use a similar proof technique to actually show that our scheme was secure. But that also didn't work. But for those of you who are familiar with BKKV, they have an algebraic lemma that I'm not going to tell you about. But their algebraic lemma doesn't actually apply in our case. So we had to come up with a new algebraic lemma and that's the main part of our result. So hopefully this motivates you to see the paper for more details. To conclude, I gave you details of a generic transformation that converts bounded leakage resilient scheme to tamper resilient. And also a high level overview of number 30 construction of a scheme resilient to continual memory leakage and tampering. Thank you. Any questions to Bawana? Let's thank our speakers for the session. Thank you.


Selamat malam, semua. Nama saya Dikyar Ganggara. Saya dari Indonesia. Ia berada di Singapura. Sekarang saya belajar komputer di Tianuswantaro University. Saya programer dan saya juga penyelidik penyelidik penyelidik. That's why I joined and lead an open source community in my campus. Call it DOSCOM, Dinis Open Source Community. I also a Mojlian as Firefox Student Ambassador formerly and now as Mozilla Tech Speaker. DOSCOM community is a non-profit organization. So for making money, I work as front-end developer at mytarget.co. And yes, my hobby is coding but I have another hobby. My other hobby is cycling. So when I try to combine my two hobbies, it will look like this. Yes, why not coding while cycling? Okay, you can find out more about me at Dikyar Ganggara.com or on social media at Dikyar Ganggara. Or we can work together at Jithub. Here is my Jithub account. Okay, let's start. Telenok OS is a project by Dinis Open Source Community. It became because we had the same problem. It's really, really hard to get started with programming for computer science student in our country. Because they need to have a thing to deal with unfamiliar development environment like installing compiler IDE and also configuration Sektora Sektora. So we create an operating system that design it for programmers. It's called Telenok OS. We, especially for newbie programmer so they can easily catch up with development environment. And we try to create, to spread Telenok OS start from small. We trying to influence other friends to use Telenok OS and then until my campus decide to use Telenok OS as system operation in about 400 computer laboratory in my campus. And this is one of reason why Telenok is great. And the reason is piracy issue in Indonesia. From this start, as you can see, almost 80% software in Indonesia is unlicensed or piracy. It's a bad news for us. But we trying to solve this problem by free and open source software and spreading on open source. So that's why we create Telenok OS from 8 years ago until now and we will release every year. And this year is in May. So, how Telenok OS can help programmer, especially newbie programmer. We create some tools or application like G-Module Installer. So, this is installer like, so you can install development environment like text editor, programming language or compiler, etc. with graphical user interface. Because newbie programmer familiar with terminal like this. So, we simplify that things by graphical user interface like this. So, you can just click what you need and just install it. Or you can bundle. Okay, the next thing is we create a T-package manager just like in Windows.exe or in Macs.dmg, just like that. So, we can transfer program or application between computers offline because in Indonesia internet is not like in here. You know, this apps also offline and available directly on DVD or ISO. So, they don't need to connect internet to install of them. And we come with two dim. The first one is dark dim and light dim. Because based on our small research to developer, they prefer to use dark dim. Because it can make you stay more longer on the front of computer. And we also create a dim switcher. So, you can easily switch dim as fast as easily as like this. And we also create a dev report. So, the user can easily report our bugs directly from the OS. No need to email or something like that. And it directly create an issue on our repository. And Telenook OS using Firefox developer edition as default browser because majority of user is developer. Okay, that is Telenook OS. And we just create a Telenook Studio. Okay, let's open. It's still in Bahasa. And it's still beta, but I guess it's a little bit cool. Basically, you can create your own operating system with few single click. Like, let's try. You can just give name of your OS. And select the architecture. You can also select the dim icon wallpaper. Or you can upload your own wallpaper. And you can also select which application you want to install. And just build. The build process is in our server. And after this, you will get ISO. So, when you install it, everything you choose will be installed. Pre-installed. We also create a project. This is under development actually. Call it modularity. So, this is content of a packet of development environment.  We bundle it as. But it's still in under progress. Okay, this is our team. So, what we can learn from here. We try small. We start small. We try to help our friends and then our campus and maybe our country. Just started small. If you like to contribute, let's go to our download.  We believe that open source can open your mind and also make this world a better place. That's it from me. Thank you so much. Let me know if you have any question. Thank you. Does anybody have any questions? Yeah. Do you have any mirrors or are you using any mirrors in Indonesia for packages? Sorry? Do you use any mirrors in Indonesia for your packages? Yeah, we have a repository, you mean? Yes. We have Ping Win. Ping Win, this is our repository. That is a local server in my campus. So it can be fast. Nice. I noticed when you were showing the slide about the cost of piracy. That the US was at the top. Yeah, but because of the total cost, right? By percentage, but it's still interesting to me. Okay. Where is this? Yeah, there you go. But the presentation is the biggest one. Right. Yeah. In Indonesia, not only software, film, music is commonly, and it's so sad. Yeah. You know. I know. Any other questions about TLINK SOS? You can build a custom image using the... TLINK Studio? Yeah. So is there any way you can verify the image? Verify. Check some... We didn't do that. We didn't do it yet. Because... Yeah, we just create and then deliver it. That's it. Thank you. Yes. This is good advice. Thank you. Oh, yeah. If you want to try TLINK SOS, you can get it. Or you can download it on TLINKSOS.org. Yeah, that's it. Thank you. Okay. Awesome.


to the cloud. Cool. Alrighty. Let's get this party started. Hello. Welcome to another fun, exciting edition of the CPC meeting. This is a regular meeting, so that means we're going to go through all of the issues that were tagged with the CPC agenda tag on our GitHub org and kind of go that way. One of the things we do need to do today, which I'll put at the end for any other business, is figure out what topics we want to cover in our working sessions for May. As always, yours truly has ideas for you, but it's up to us, so we'll cover that of course when we get there. Let's go to announcements. Announcements. Who's got announcements? Obviously, we always have announcements about OpenJS World this time of year. In case you haven't done so already, we're really hoping that everyone has registered for OpenJS World. We did get the speakers announced on our website this week, and so we're really excited about that, as well as some of the Slack channels and stuff are starting to get set up. If you want to do some pre-event conversation about the topics or talk to some of the speakers, that kind of thing, join us in those Slack channels. Of course, there's still space for community talks from our projects, because we're doing this like Netflix style on demand. It's really easy for us to make sure that we're covering all of the content from our projects that they might have to share. If you've got something from one of your projects and want to make some space for a lightning talk or a short session or something like that, we can do that. Let us know. Those are kind of our OpenJS World-related things. The other little thing that I have is that tomorrow morning at 8am Eastern, which is definitely earlier than I like to have any meetings at all, but still, it's worth it. We're going to be talking with Marcos Caseros, who is a new W3C employee, but he's the chair of the Spec Editors Community Group, and he lives in Australia, so hence getting up at 8am. We're going to talk about that exciting community group and record it so that the rest of our standards working group community can watch it later. But you're welcome to catch that live, and the link to all of that info is in the standards repository. If you want to get up early and talk to the nicest Aussie in all of the W3C, Marcos, join me. I will be highly caffeinated at that hour. Project announcements? Anything like that? Whales wins? What have yous? I mean, I'm not ready to release it yet, but the next version of NVM will actually have limited Windows support beyond just WSL, like PowerShell and Git Bash and stuff. I'm using very hedged, fuzzy words around it, like maybe and things like that, because I expect a flood of bug reports, and I have no way to test them myself, because I have no Windows machines. But if it, assuming that it works, then a lot more people will be able to use NVM. It's exciting, congrats. Preemptively, congrats, and also preemptively, like, you know, condolences for the bug reports that you will likely get. All right, cool. That takes us down to board meeting updates. Sarah and or Michael, you all want to share any fun stuff? We had the board audit and finance committee meeting just before this meeting, so we did discuss the request around the travel fund, and there's going to be a recommendation made back to the board, so hopefully we'll have an update on that. As we mentioned before, you know, the discussion was positive, so, you know, just that we'll have closure on that fairly soon. Awesome. And let's see. That's it from that. Now I guess we can move on to our, our regularly scheduled slate of issues. Our first issue is issue number 747, and this is for a call for Slack moderators and volunteers for our newly formed app moderators team on our Slack organization. We want this for like two purposes. One is the long term sort of ongoing year from now and sooner, like, if somebody has something that they need help with, or they see something that looks spammy or whatever, they can just at tag at moderators, and whether Joy's online or Brian's online, this team would be able to, like, clean it up and handle that. The second need is actually more imminent for OpenJS world, but we're hoping to have is a team of us who are able to just help, you know, keep things clean and safe for our OpenJS world attendees who may be joining to participate, particularly in those chat channels around the tracks that we have, and to help MC and moderate those channels when we have the speakers available for Q&A. So this is my request. I know not everybody may be available to do the moderation on the day of the event, but if you think you would be around and available to do it longer term, you know, we can get you added there. Or if you'd like to raise your hand to serve as a MC for one of the channels, we'd love to have you too. Questions or comments or observations, concerns, volunteers? I would just add that we have identified four different time zone chunks where we're going to invite our moderators slash MCs and our speakers to sign up for that way we can hit every region around the world. So if you live in another region and you can sign up for a time that's convenient to you, or if you're here and would love to backfill some of those hard hours and other time zones, we'd appreciate that as well. So I will add those time slots on the issue. Okay, so if there's not any other questions, I know some of you've already like privately volunteered with me, thank you so much, but otherwise, you know, ping me in Slack or just raise your hand on the issue and we will get you all signed up. Honestly, doesn't look like it's going to be a heavy lift, but it's a good thing to have. All right, that moves us to a probably trickier and lengthier topic. This is issue number 745, the voting CPC members election. So as you all may recall, in our charter, what we do is have a couple of representatives from all of the CPC members elect folks to represent them in the voting CPC members group. We need to run two different elections as Emily points out, one for the non-impact projects and the other one for the regular members. So this is something that typically myself and Brian Warner as foundation staff execute. We have talked about finding ways to automate this so that we don't miss the election windows as we have done in the past. And then also too, we need perhaps to add some language to make it more clear that like in the event that we accidentally missed that window as we have in this case, that we don't go without these representatives that they serve until the next election is run, for example. So a couple of different sort of hygiene things that this issue has popped up. So I think the first thing that's very tactical and practical is we need to open a nomination issue for both of these spots. And then where we may have multiple parties nominate, run that election. Other insights or observations here, this is what the second or third time we've done this one now. So it starts to feel a bit more routine. So I guess my only question is what's the next step in terms of kicking off the elections? Is somebody got the ball for starting that? Unless there's something we want to do from a process perspective and differently than I would suggest that the next step is to open the call for nominations. We can do that on an issue and then also send it out to our projects list as we have often done in the past and kind of go from there. Typically that's been the CPC chair that kicks that off and obviously Joe's out today and we may want to go ahead and get this going so I can certainly copy pasta a past language to open this up. But I don't want to lose the the insights obviously that we've highlighted here one being a need for you know the language that may help us in the event that we make this mistake in the past and in the future and the second being a way to automate these issues so that we don't accidentally do it again because you know we probably will. Alrighty well so and also if I could just request somebody help take some notes here um I'm trying to uh I'm just taking a note that you volunteered to to create the issues right? Yeah I went to go do then the add the minutes from some of our last couple meetings and realized we hadn't done so good about taking taking actual notes so uh probably time to pester on that again thanks Michael. Alright um okay well I suppose uh if there's nothing further on 745 we can move onward. The next issue on our list is issue 744 this is an issue to remove growth project distinction on the open js foundation website and this one feels um seems like a brian issue yeah seems like brian ought to be doing that right now during the cpc and in fact yeah I'll take care of that right now okay it's like who's to say brian didn't already do it I don't know I haven't been to the website today uh so don't go for another 10 minutes okay okay thanks brian no problem cool um great great so issue 725 add travel fund allocation for 2021 so this is the update that that Michael just hopefully gave from the audit and finance committee meeting which was like literally ended right before this call so the the freshest news possible was delivered until and it looks like we're going to have um next steps and closure on this soon so uh thank you Michael and Sarah alright issue 699 um this let me scroll down and see what is the latest on this so okay and Sarah Toby's really the one running point on on this do you know um the issue hasn't been updated since we last met do you have have any updates I don't but Toby and I are meeting to uh to uh our meeting some time to talk about it so that's what I got um I think it might be worth having like a circle up so we can figure out strategy um would you like us to take this um agenda okay we can take it off we can take a label off leave the issue open obviously but then y'all could put the label back on when they're when you're ready to report something back to the cpc regular yeah that sounds great yeah I can get one update on my wall I think right now just so you know if you hear that scratching and if you see me just a quick update if you all saw I think there was a blog last week the Linux Foundation is building out a research division I've met a couple of times with the new head of research and flagged our request to do some DEI stuff as well I know it's maybe not the going to be super early on on the editorial agenda but it will come but anyways we can follow up when we have that other meeting but that's cool very cool yeah that'll be great if we can get additional support on that that's cool um the uh next item is 632 uh this is provide implementation guidance for dco slash cla and this has been sort of open for a while because we are working with an open source maintainer on updating the pro bot dco um so we don't expect it to move terribly quickly but just in case brian do you have an update on this yeah so I've been talking a bit with um with the maintainer and also some other folks who work on pro bot um the maintainer is busy uh but has said that they are able to review it hopefully sometime soon um I am trying to get some other eyes on this as well because that that may also help lighten the load um just basically making sure that the the pr which is non-trivial admittedly uh making sure that it does actually going to do what it's supposed to do so um if anybody would like to volunteer to do an unsolicited code review on it that would also be cool um but at this point it's it's one of these things where it's you know it's it's out of our direct hands um and we're just going to I guess have to continue to wait for uh for them to have the time to really get through it all right well thank you for your patience and working through that and obviously um you know uh thanks to the pro bot team too for their patience with us um okay that takes us actually to the end of our tagged agenda issues we do have things that were called out for any other business and because we didn't quite get an issue filed with the array tag in time before this thing agenda was generated um and that big big kind of exciting thing is uh anticipating the graduation of some of our upcoming our incubating projects nbm slash jordan is one of them jordan's got a project charter for our review and I think this is basically the last piece um we we met earlier this week yeah so I just dropped the link to the charter in the zoom chat it's not on the main nbm repo it's on my personal fork so it's like public it's just not advertised um I'm I was waiting to push it up to the main repo until uh Robin and Jory had kind of given me the go ahead to do that but it I think it's pretty much ready so feel free to review it now um it's largely I basically just took fastifies and like replace the project name and you know took out some sections that didn't really apply and you know so it's it's um it should be very similar to that and given that there's a single maintainer and no team structure or anything like that it's it's a much simpler uh governance at the moment so um we do require a majority of our um our cpc members to thumbs that up on so please take it take your time and go mosey on over and review and so we can get that last checklist item done for nbm the other two projects are anticipating their chart I'm anticipating getting copies of their charters for for you all really soon so um be on the lookout for that if we can get those approved as part of our kind of last mile thing then we can we'll be um well on track for uh just celebrating their graduation at open js world which we would be very excited to do in terms of visibility have we I'm trying to remember have we opened an issue in the cpc repo that says please approve this charter over here and then we can at mention the cpc members because I'm not sure we can do that on the issue that's in the mvm repo the issue that uh the checklist we're using is actually in the cpc like the uh project test project status repo um which is owned by the open js foundation so I think we can at mention everyone there um yeah we've got that but I think also Michael might be talking to um what some other projects have done in the past which like here's for example in the zoom chat here uh from fastify where Mateo just opened an issue that said you know fastify charter review and and here's here's the link um so is that what you mean yeah that's good that's what I'm that's what I'm thinking so that there's a clear place to have a plus one and you know that then stays there versus it's like we plus one the checklist I'm not sure if it's as clear maybe you could checklist uh comment or something but I think this makes it easily discoverable there's an issue there's somebody goes and looks they can find it it's in the top of the list I'll file that right now and we'll close it once we say we have enough people so okay thanks um cool so thanks for for taking a minute to go take take a look at that it's really important um for just sort of our last uh you know onboarding steps um and very helpful to the projects so thank you very much um the next any other business item uh is just to call out that we have two uh working sessions coming up in May and we should uh determine what we want to do what projects we want to work on with that time the last couple um that we have taken on include our um technical project strategy which was last week and and then prior to that was JSlandia and we've done some sessions on DEI and um code of code of conduct improvements um on that note we do we do have a PR um on some COC improvements that were was driven out of those those sessions ready for your review um so we could use one of those working sessions to um memorialize that PR or and or take up an additional uh improvement which we've we had identified a shortlist so that is one uh one's one option um a second option is you know going back to the technical project strategy we had a actually that seemed to be a topic that there were several avenues that we didn't quite follow all the um calves of in our first session um but obviously the options are boundless in fact and I'm just curious if anybody has a uh preference or dealer's choice to talk about Slack I'm also keen to talk about just like improving people's experience on Slack what's what's the issues with the experience on Slack just this context oh just like making it like really welcoming and you know making it easier to find sub chats that you might be interested in or you know that that kind of thing useful there's like 1400 good sorry I got a conference uh I think I think something that might be useful would be a little bit more guidance on like what acceptable use for the projects is like I don't think there's been any problems but I think uh having some like pointers on like what it could be used for uh would be helpful in like making it more of a good space for to actually like the projects to engage uh not that like like I think node has done a okay job I've also been the one doing it so of course I'm gonna think it's an okay job but like in setting things up um but yeah like having having you know different kind of recommendations on how to do things we might also want to get on the path of something like uh what CNCF does for the Kubernetes Slack where it's all managed through YAML and like people can't create random channels because like I can just create channels uh which some random person could also come create channels and like not great channels or something or like name things with bad names or something like that and we'd have to do do work um and that that might also help kind of codify how how this experience goes a bit more to uh if we kind of bake that in from the beginning of this discussion but uh yeah so sounds like Tierney would love to talk about Slack sorry I have opinions about Slack other other um ideas or preferences okay all right well let's let's do um let's do Slack and also the uh kind of follow-up slash take two of um that initial exploration on tech project strategy that we started another idea could be maybe identifying other potential collaboration spaces that we would see would be helpful for the CPC to help drive Michael what do y'all think sorry I was just distracted for a second what was the question again maybe use a working session to identify some other you know uh collaboration space uh topics that we would want to encourage yeah that's a good idea or I mean we could continue on sort of related to that we could continue on with the strat you know we're trying to come up with that sort of project areas or I forget the word you the project portfolio strategy yeah I think we still have a bunch to work on that so that would that would be a good one cool um well I we've got many weeks worth of meetings potentially um I will take the opportunity to call out issue um 739 which has that schedule for the rest of the year um and so if there's actually a session that you want to host or drive for a working meeting for example feel free to go edit that issue make yourself a little you know spot and super do it you know so otherwise I'll I'll pester you once a month and probably more so there you go um cool and then uh the last uh the last thing that I uh wanted to share was was actually that pull request that I mentioned earlier um so the group had been meeting um for a couple weeks and then a small group went and took a pass at um at updating we've got a couple of outstanding sort of questions and comments which I think are perfectly fine for us to work out on our work out on our pull on this pull request but um thanks to Michael and Anton and Matteo and Joe and Sarah and Divya and others for their um work on this you know draft of the document so we're ready for for broader cpc um comment uh and input and I just tried to port over all of our all of the sort of outstanding comments um from from the doc from our google doc so reviews welcome there um and that happened right before this meeting so I don't suspect anybody has had a chance to read it so thank you um cool any other business oh Tierney's got a great little note uh Joe ran unopposed at the no js com com and will continue to serve as the com com rep yay Joe and abstention of course thank you Joe for continuing to do that uh other private news or anything fun anything fun nothing fun well you have squirrels that are going to fall through your yeah I don't know what's going to repeat that what is going on with the squirrels I don't know I just hear like in our walls you could just hear it scratching away I'm just waiting for it to break through the drywall any second just jump on my face I had that the other day and I banged on the wall a few times and they went away so you can try oh I've been banging on the wall I don't think these these are new york squirrels they're not interested they're like not afraid of anything that's great all righty well I think uh uh the squirrel report being concluded I will stop our recording uh there we go


While studying at the University of California, Berkeley in the United States, Masayoshi Sun developed an electric dictionary that helped people translate languages. He sold the project to SharpCop for $1.7 million while studying at the university itself. He worked on another project that gave him $1.5 million. With a total amount of $3.2 million, Sun founded SoftBank in 1981. It started off as a company that distributed software, a company that provided a bank of software and thus the name SoftBank. It has started out as a software distributor but it has expanded rapidly. It has also entered into sectors such as telecom, internet, energy and robotics among many others. The year 1999 proved to be a tough one for Masayoshi Sun. He almost went bankrupt when SoftBank stocks went down by 99% when the dot-com bubble burst. Masayoshi Sun lost a staggering $70 billion, the largest loss an individual has ever recorded in history. But Sun worked his way back up to rebuild his business by pursuing Vodafone Japan and turning it into an extremely profitable endeavor. Since investment journey started way before Vision Fund, one of its biggest investments were made in London Bay Semiconductor Design Company arm, a staggering $34 billion was found. Sun has also invested in Yahoo and Alibaba. In 2017, SoftBank launched the popular $100 billion technology-focused Vision Fund. The fund comprised of contributions from Apple, Qualcomm, Foxconn, SharpCorp, Abu Dhabi's Mubadala Investment Company and Saudi Arabia Public Investment Fund. Sun convinced Saudi Arabia's Crown Prince Mohammed bin Salman to invest $45 billion in the Vision Fund. The Vision Fund made SoftBank the star investor of the Silicon Valley and the entire world startup ecosystem. It made investments in iconic companies of the world including WeWork, Uber, DD Chakshing and Flipkart among many others. It was considered that of a genius, started getting questioned after a series of incidents. The most iconic companies of the Silicon Valley and SoftBank, WeWork and Uber, failed with their iPhones. While Uber failed to put a convincing show as its stock slipped immediately after listing and is trading below issue price even today, WeWork cancelled its IPO a week before its launch. Overcapitalization is being doubted one of the reasons for their failures. Experts started questioning the Japanese conglomerate's strategy of pumping more capital than what the companies required. The stock market did not accept the SoftBank's growth only and less profitability strategy. For a lot of damage control ever since, he came up with a rescue package of $9.5 billion for PropTech startup WeWork. According to reports, SoftBank has been telling its portfolio companies to focus on profitability before thinking and planning IPOs. The newly launched Vision Fund 2's future remains uncertain as many of SoftBank's investors are now hesitant to make further investments. Moreover, SoftBank recorded a loss of 704 billion yen in the July-September quarter. All eyes are now on how Sean sets the path right.