Good morning and welcome to my presentation. First of all, I would like to thank my mentor, Nathan, for inviting me to talk to you here today, and I hope that I'll be able to present you with something that you would find interesting to listen to. I would also, from the outset, like to invite your comments and suggestions. I have no handouts, but I have two papers, draft papers, which I'd like to share with you if you are, after this talk, interested to know more. I'm basically a field linguist. I've described a small and endangered Tibetan-Burman language spoken in the Eastern Himalayan region. I've written a grammar of that language, and then during my field research, I also collected data on seven presumably related linguistic varieties, and right now I'm using these data to reconstruct the purported proto-language, which I've called proto-Western Kobwa, and today I would like to share with you a few ideas on the onsets, looking from the perspective of two of these varieties. I'll start with a short introduction, because probably the Kobwa languages are, you are not very familiar with them, if you've ever heard of them at all. I will give a short introduction to my data and the methodology that I followed, which all of you are very much familiar with, so I'll not discuss that in detail. I'll quickly show a few trivial and regular correspondences. Again, not very surprising, not very interesting, so I'll just go through them very quickly. And then I would like to focus on some of the more extraordinary, not really maybe in a typological perspective, but at least in this case, what caught my attention, which are the pellet-laced onsets, the rothic onset clusters, juvenile onsets, voiceless onsets. And finally, I would like to show you a few noteworthy correspondences with other Tibetan-German languages. Kobwa languages are a small cluster of supposedly related languages spoken in Western Arunachal Pradesh, which is the area which is bordered by Bhutan in the West, Myanmar in the East, then the Tibetan Plateau and the Himalayas in the North, and the Brahmaputron Plains of Assam in the South. Based on research materials that became available basically only in the last two decades of the previous century. It was Jenshin Jackson-Sun who first came up with the hypothesis that these languages, instead of being just some kind of a residue of languages, Tibetan-German languages actually might be related to each other. Since then, his view has been both adopted as well as challenged. However, till now, there has not really been a lot of or any linguistic evidence which either supports or discredits his view. Among these Kobwa languages, a certain subgroup can be discerned, the Western Kobwa languages, which are mentioned here, basically four languages with a total of eight individual varieties spoken by less than 7,000 people in the Western part of Arunachal, with as close as genetic relatives Puroik and Bugun. All these languages must be considered endangered, not just because of the low-speaker population, but also because of the rapid socio-economic developments in this area, which are really very rapid. This map shows all the hitherto identified Kobwa languages, the Puroik area, which is in the central and western part of the state, huge geographical area. They are speaking this language interspersed with Nishibangru and Miji speakers. Here, we find the closely related mutually intelligible Bugun varieties. Here in the western part of the area, we find the Western Kobwa languages. Kisfi and Duhumbi spoken here. Then the Sautang varieties spoken in this small area here and the Sherupen variety spoken in the Tengah river valley. As you can see, this is a relatively fragmented area. There are speakers of other more dominant both linguistically as well as socio-culturally more dominant speakers. In the neighborhood, the Tangla speakers, for example, who separate the Kisfi and Duhumbi from the other western Kobwa speakers. There has been a lot of language contact, both through contact languages as well as to inward migration and intermarriage, not just from Tangla also, from Central Bolish Brokpa, from the Tibetan side, Tuchangacha speakers from Bhutan, Kengah speakers from Bhutan and in the eastern part the Miji and the Russo Aka. So a lot of contact language influence, which is important to be aware of. My former colleague Ismail Lieber here and myself, we did a lexico statistical study, a Kognut count analysis with sensitivity analysis and here you can see the results. We used 100 so-called stable roots and around 20% of these stable roots are shared among all the Kobwa varieties. A percentage which goes up to around 40% between two individual Kobwa varieties. So that's not a lot but in an area like this with so much of language contact, considering stable roots which are not very prone to borrowing that might be indicative. We can also see that the western Kobwa languages are the square in the left upper corner, Bugun languages in the middle and the Poloik varieties which show most internal variation in the right lower corner. So there appears to be a rather clear subgrouping. My research is based on original field data of all the eight known western Kobwa varieties. I started out with a word list of more than 550 lexemes which were from the most commonly used word lists but also regionally, socioculturally, environmentally specific words which I collected based on my own experience in the area. A minimum of two speakers from each variety and I also collected additional lexemes based on sentences etc. to find more about the morphology of these varieties. Finally I went back to elicit some missing lexemes like the gaps in the cognate sets and also some interesting forms on basis of particular onsets or particular rhymes which I told that might be interesting to have some more information about. Methodology you will be very familiar with. One important thing to mention is perhaps that I started out with a comparison between Duhumbi and Koitam and the reason for that is that Duhumbi is rather conservative as far as rhymes are concerned. It has innovated a bit more in the onsets and it's also been on a more contact language influence but still the rhyme patterns are very interesting and Koitam is rather representative of the Sautang and Shendepen varieties. Here are some trivial correspondences nothing out of the ordinary here in which all the Western Cogba varieties have the same reflex from a reconstructed protoform. Regular correspondences where they don't all have the same reflex but still these reflexes are not very surprising, not very special and easily derivable from an onset. So rather than that I would like to focus a bit more on some special onsets. First of all there are a number of cognate sets where Duhumbi and Kispi have a voiceless palatal fricative onset which corresponds regularly with aspirated palatal and alveolar africates in the Sautang and Shendepen varieties. So my proposal here is that this derives from palatalized plosive onsets both in the voiceless both the voiced and the voiceless counterpart there in which it is the Sautang and Shendepen varieties which actually show a distinction between an aspirated reflex and a voiceless reflex. There is another correspondence set where a Duhumbi simple bilabial plosive onset corresponds to voiced palatal africate onset in Koitam. However, this is only when followed by an open high vowel and this is actually a homophonous set of a homophonous correspondence four cognate sets in which we find this correspondence which I've attributed to the open high vowel and as you can see in the second set of examples the influence of an open high vowel or open high vowel rhyme on an onset can be rather distinctive. So whereas normally we have a correspondence of a bilabial plosive in all varieties there are a few cognate sets where we see a bilabial plosive in Duhumbi and Kisvi correspond to the alveolar africative, voiced alveolar africative, the sibilant onset. So here we can see this distinct influence of high vowels and high vowel rhymes. You may notice that there is a kind of a noticeable correspondence between western ko-boa bilabial plosive onsets and nasal onsets in the Tibetan language. This is something that I will come to a little bit later. Then the second is the robotic onset clusters. There are certain correspondences that are irregular in the sense that the correspondence itself is regular. The cognate sets are regular but there is a different kind of reflex in some of the varieties. For example, here you can see that in the first group that the ko-itam reflex is an africate whereas we would have expected a simple velar onset. So in this case I have reconstructed the robotic onset clusters both with velar stops, with bilabial stops and with a voiced alveolar africative onset. So interesting is perhaps the phonological change that affected these onsets. These are regularly simplified in the Humbi-Kispi and the Sharedupen varieties to a velar onset but they became palatal africates in ko-itam, raung and jirigau and there are very peculiar retroflex africates at least in an aerial perspective for the western Kogwa languages. It's more common in Rushi's languages of the retroflex africates. I have only one example from the voiced onset and there are several examples from aspirated velar onsets. The reflexes are a little bit different in the case of a voiceless, an aspirated velar onset. There is a glottal africative onset in jirigau with a subsequent contraction of the root and the prefix. So in the first case of the wild boar se-hen becomes sen. In the second case, barking deer se-hi becomes si. But we see that the glottal africative onset has been preserved in the case of bone which might be attributed to the vocal prefix instead of the prefix's sha, the sha prefix, the meter animal prefix. So this is the only case in which there are a little bit unexpected reflexes we would have expected, for example, unaspirated, unvoiced reflexes also in Duhumbi, but as you can see in the case of barking deer that correspondence holds. But in the case of wild boar and bone, there is aspiration, which may be attributed to a prefix. Clusters of a bilabial, plosive, and rotic medial are simplified to bilabial, plosive, onsets in Kisbien, Duhumbi, but have been preserved in the sartang and shedepen varieties, although the rotic became a lateral medial in most sartang and shedepen varieties except for Rahum, which has, in most cases, well, in all cases, preserved the rotic medial. The reason for not reconstructing a bilabial, plosive, and lateral onset cluster here is because there is no other evidence for lateral onset clusters. So veeler and lateral onset clusters, I have no evidence that suggests this, but as you saw in the previous slides, there is evidence for a veeler and rotic medial onset. And I've earlier shown that bilabial onsets followed by a high vowel or high vowel rhyme have divergent onset reflexes. The same is the case with these rotic onset clusters. So the reflexes here are different from what we would expect. So again, it is this high vowel or high vowel rhyme, which seems to have some kind of deviating influence on the onset. These correspondences are the main source of the Duhumbi onset cluster, pshe, which indeed itself occurs only when followed by a high vowel or a high vowel rhyme. In the case of swell, fill, full, and four, the onset reflexes actually, in my opinion, may not really show for a onset cluster, but perhaps rather a prefix or a pre-initial rather than the onset cluster. But I'm sure there are people here who have their own interesting ideas on that, so maybe we'll keep that for discussion later. Now I would like to pay some attention to a rather modally mixed bag of correspondences that I was kind of left with after setting up all the other correspondence patterns. We see that the semantics of these sets are very clear. There is not much case where you have to look for semantic cognate forms, which are very different. And even the rhyme reflexes are rather predictable. They are regular. So the onsets are the only ones that are a little bit strange. And based on the comparative evidence, well, first after internal reconstruction, like after excluding other possible reasons, for example, other possible simple onsets, relativized onsets, rotic onset clusters, or possible explanatory phonotactic conditions, it is the comparative evidence where I found some information that this might actually derive from uvular onsets. In the Western Kogwa varieties themselves, uvular onsets are not attested, except in Duhumbi where it occurs an allophone of a aspirated velar onset. For the rest, they are not a distinctive phoneme in any of the Western Kogwa varieties. So like I said, both the internal evidence and the form of onset correspondences that do not fit in with any of the other correspondences and comparative evidence from, in this case, quite often old Chinese, or basically always old Chinese, suggests that in these cases, rotic onset clusters of a uvular plosive can be reconstructed. And in this case, it's the unexpected rhyme reflexes, in the case of soybean and egg, which actually necessitate a labialized onset. And in combination with the divergent onset reflexes, I propose that these derive from a labialized uvular stop, which in the case of koi tam suk has actually been contracted. So there is, again, the prefix sha hua, which becomes se yuk in koi tam and is then contracted to suk. For example, in Jiri Gaon, we still find the original form se yuk. And in the case of hand arm, it is probably the complete absence of a prefix that resulted of the loss of the onset in the satan and shared the pen varieties, where they have now retained only a uvular vocal onset instead of the expected palatal glide. So it would have been yuk if there had been a prefix, but because there was no prefix, the palatal glide was lost and it became yuk. There are a few cognate sets where a Duhumbi and Kispe labial approximate onset corresponds to palatal approximate initials in satan and shared the pen. I propose that this derives from voiced uvular onsets, which, again, is kind of supported by the comparative evidence from Chinese, old Chinese. There is another correspondence where vocal onsets in the western cobra varieties correspond to voiced uvular onsets in old Chinese, which I will show you in a few slides. There are several cognate sets between western cobra varieties that cannot be explained. And here I would like to reconstruct voiceless onsets in which the characteristic reflex is actually a glottal fricative and at least one of the varieties. Why, in the case of voiceless nasal onsets, the glottal fricative is in Duhumbi, whereas the nasal is in the satan and shared the pen varieties. But it's exactly the opposite when we look at the approximate onsets, in this case the palatal and the labial approximate onset. That is something that's still a bit of a mystery to me. Here are some of the examples. I think considering the time, I will not go much into these. In the following slides, I'd like to present some additional evidence of relatively unique correspondences between western cobra and other Tibetan-Burman languages. Some of these correspondences were already identified before, and I would like to present some additional evidence for these. Characteristic for the cobra languages is the correspondence between plosive onsets with nasal onsets in other Tibetan-Burman varieties. I saw already in your handouts that that also is a correspondence between Basque and Proto, or considered to be a correspondence between Basque and Proto-Indo-European, so it might not be that typologically that strange. But for the Tibetan-Burman languages, except for a few Bisou varieties, this is probably quite exceptional. Some examples of these correspondences are provided here with the western cobra reconstructions, having a plosive onset, but the comparative evidence from other Tibetan-Burman languages showing a nasal onset. This correspondence is also found in the Vila point of articulation, as these examples show. Here a western cobra-Vila plosive onset corresponds to other Tibetan-Burman-Vila nasal onsets. And there's even one case at the dental point of articulation, although the evidence is only for Duhumbi and Kispi, because the Sartang and Sherdupan varieties have a nasal onset as the other Tibetan-Burman languages. I have noticed how somehow correspondences of Proto-Western Cobra stop onsets often tend to correspond to all Chinese nasal onsets in type A syllables. Some of these examples I already showed before On the other hand, Proto-Western Cobra nasal onsets often correspond to all Chinese nasal onsets in type B syllables. So this is perhaps a kind of a noteworthy correspondence. However, as always, where you find regular correspondence patterns, you have your exceptions. Where either Proto-Western Cobra nasal onsets correspond to all Chinese nasal onsets in syllables of type A, where we can see that these syllables pelletalize, the onsets pelletalize in western cobra, or we have Proto-Western Cobra stop onsets that correspond to all Chinese nasal onsets in syllables of type B. Now, because I'm still a little bit unfamiliar with the distinction between all Chinese type A and type B syllables, and the various theories that surround this, I cannot yet draw any conclusions regarding this, but these are just my observations, and I'm happy to hear people's ideas and suggestions. Another observation is that western cobra vocal onsets often correspond to a sibilant onset in other Tibetan Berman languages. Some of the cognate sets that show these correspondents are presented here. A major outstanding issue is shown in the last two examples where a voiceless LVL or fricative onset in other Tibetan Berman languages just regularly corresponds with a sibilant onset, or in some cases a glottal fricative onset in the western cobra varieties. So what are the conditions that result in de-bucalization or in preservation of the original onset? This is again something that I will have to look into more closely. There is another set of correspondences where western cobra vocal onsets correspond to reconstruct all Chinese voiced uvular stop. In these cases, although it's tempting to reconstruct a voiced uvular stop for proto-western cobra, I think it is prudent to just reconstruct the most straightforward onset, which in these cases would be the vocal onset. Maybe later evidence will actually show that this derives from all uvular stop onsets. Then there is a regular correspondence in the western cobra languages between voiceless dental nasal onsets initials. Two examples of this are given here. In some cognate sets, we can observe how the voiceless dental onset in western cobra corresponds to a voiceless lateral or voiceless or voiceless lateral onset in type A syllables in all Chinese. So again, just an observation of quite a regular pattern, at least in those cognate sets where I could find comparative evidence from all Chinese. Although you may not really agree with all my semantic correspondences here. A rather curious correspondence that is nonetheless very regular is the correspondence between a Duhumbi and Kispy dental plosive onset and erotic onset in all other varieties. I propose that this derives from an onset cluster of voiced uvular fricative and erotic medial. As you already saw, erotic medial onset clusters are not uncommon, at least in the reconstruction. It's also noted how this western cobra correspondent quite often tends to correspond with dental plosive onsets in all Chinese. So again, an observation of a possible comparison with all Chinese and other Duhumbi languages. Okay, wow. Sorry, did you send that off? You didn't have to use the... Okay, thank you very much for your attention. If there are any questions, suggestions, ideas, then I would be happy to discuss them since there is more than enough time anyway.


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And thank you so much for inviting me. Well, I should say that I first got acquainted with you, wonderful mathematics when I was a student at the, in the 70s. But we met first in the 90s and since then Luki is a dear friend and amazingly kind and gentle person, deeply appreciating books, music and nature. And thank you, Luke, and many happy returns of the days. Now, this is a small work with Spencer and let me start with a construction due to him of some cycles, homologically equivalent to zero. And as usual, all we know that cycles homologically equivalent to zero are interesting object and construct them with a sort of arc. So we start with a family of algebraic varieties over a complex disk and initial pointers. Zero is here. Oops. And I assume that Y is smooth. The one that singular point of F have just one point, Y is zero. And it sits in the fiber over zero. And the point is quadratic. Well, and then let's consider a blow up of Y zero at this point. Let's call it X. And then we see that the exceptional divisor of the fiber of pi over small y zero is an undegenerate quadratic denoted by Q. Well, and I assume, now let's assume that the dimension of Y equals to N, sorry, to N. And then Q has dimension to N minus two. And so we can, it's even dimensional quadric. And so we have, we have it's two rulings. And definition, I will refer as block cycle B is the difference of two rulings of the two rulings of Q, but I wanted to view it as an element of the Chao group of X. Well, the co-dimension would be N. Well, again, we can see that I'm not lying on the quadric, but inside of who X, and you can ask if this cycle would be homologically equivalent to zero. And here is a small M. The next conditions are equivalent. So the first one is that B is homologically equivalent to zero. The second one would be this. Let's consider the local system of homology over the puncture disk and the monodrama action. So the first one is that B is homologically equivalent to zero, and here is a small M. And the monodrama action. Well, I can see the homology of degree two N minus one of I versus the rational coefficients. And it is not triple. Yep. We don't see the bottom line. You don't see the bottom line. Okay. So I will. Okay. So let me pass to the next white board. And right. Now you don't see anything. Okay. So. Unfortunately, I don't know how to scroll the thing. Oh, beyond she's at all. Okay. Okay. So the monodrama is not trivial. Okay. Well, okay. So anyway, well, so this condition often. And you check actually the second certainly and this happens pretty often. And for example, let's consider the case when M equals to one. And this means that we have a family of course. And with the generation with single quadratic points, a point and there should could be two possibilities. We have either one, one component. Or two irreducible component of the fiber. And in the first case, the local monodrama is. Non trivial. So the lemma, the conditions of the lemma hold. And then the second case, it's trivial. Maybe I should also say that if we get our family from a left sheet's pencil. On a given variety of them. The conditions of lemma will, will be mad if the degree of the left sheet's pencil is sufficiently high. Okay. Now, let's formulate. Let me try to formulate the theorem. Let's consider. Excuse me. Yes, yes, I assume that it's proper. Sorry that I did not tell it. Well, from now on, I will assume that the condition of the lemma are mad. Now consider our family. Variation of mixed hot structures that I can see that I mentioned in the lemma. You, and maybe I will twist it by 10 to make it to have a weight minus one. And then I do not buy the limited hot structure. In other words, the nearby cycles for this local system. Since the monodrome is non-travel and the point is quadratic, that's fairly easy to see how the hot structure, how it would look, would look like. It will have three weights, minus two, minus one, and zero. And the associated graded portions for the weight filtration. The zero is one will buy the morphic to Q of zero. The next one is actually intersection. Camology of degree two and minus one of the singular fiber. They stop. Oh, just a moment. Something bad is with pencil. I should call my daughter. Wait a moment, please. Yeah. Stop writing. Now wonderful. And the one weight minus two is Q one. Again, it's as a morphic to Q of one. Not exactly canonical as here, but at least you can, if you consider the action of the monodrome as a thing, then they open the bottom quotient are identified by the operator one minus monodrome. Or monodrome minus one. Okay. So the picture looks like this. And now let's also look at the hot structure. Well, and let's look at as a real hot structure. And then there is abstraction to do it splitting as a real hot structure. So when we have weights, which are next to each other, then the things splits as a hot structure, but there is could be a non-trivial abstraction of splitting of the whole thing. And this would be actually a real number. Yes. And our hot structure. This is a real number which is defined, could be defined as follows. Take a generator in the quotient Q of zero and say one. And then we can leave it to say one tilde, which lie in the zero term of the hot filtration. And then we can actually leave it so that its difference minus with the complex conjugate to itself. So the imaginary part of one tilde will actually lie in the minus two term of the hot filtration. There is a choice of such lifting. And this is a real number, which is imaginary part of the hot structure. And this is our abstraction. And well, I don't know the right name. I don't know which local index or something like this. And the theorem gives an interpretation of this abstraction to splitting in terms of, well, it relates to the block cycle. So let's explain it, let's consider the situation when everything is defined over Q. Then everything, I mean the family came from a family of course over Q. And also let's assume that the block cycle is also defined over Q. Then we can consider the height. The block cycle is logically equivalent to zero because of our assumption in the lemma. And so we can consider its height, its height bearing with itself. And the theorem asserts that actually this height bearing and I will recall how you define it is actually equal to this abstraction to the splitting of the hot structure on the limited hot structure that we talked about. Let me formulate it more modestly that this will be not a question of the real numbers, but model combinations with rational coefficients of logarithms of primes. In a sense, you have to do it because if you multiply our function asked by some rational number, non-zero rational number, then certainly the zero fiber would not change and the height bearing would not change but this abstraction to the splitting will be multiplied by the logarithm. One should add to it the logarithm of the number will multiply our function. So you will get this. But in fact, there is some unfortunately conjecture on the level of our due to our ignorance at the moment. So model of some rationality conjecture there will be actually true equality of the numbers and again I will say a few words about this. Also, let me say that the theorem is actually very easy and the proof is essentially a recollection of all the definitions and then it comes by itself. Though the two numbers are seemingly different but still the proof is quite easy. So what I will do, I will explain actually a geometric version of this assertion and then say a few words how to change what should be changed in the argument to make it to make a very specific statement. Well, so I need to recall collection on I should say that I was playing with this a long, long ago in the middle of the 80s and somehow both at that time the two subjects the high-pairing and vanishing cycle somehow became disjoint in my head and this work is just an attempt to draw thread between two seemingly different points. Well, so in the geometric story what I will do is to replace so before we considered your familiar course over Q but now I will replace Q by the generic point of a smooth complex curve I see and let's see what will happen. So we have a smooth complex curve C and we will consider it's smooth compactification the smooth compactification C bar and below we will play all our shifts we will play with Q-shifts Q-hot sheets as were defined by Marie Heikassaita so all this everything I will do this will be about Q-hot sheets. Well, now suppose that we have on our C we have a local system of weight 1 weight minus 1, okay and then we can extend it as usually by an intermediate extension or which is by invariance of local monodrama well and now I need the following which is which comes very easily just playing a little bit with weights and the claim is that let's consider extensions the group X to 1 of extensions between Q of 0 on C bar and the middle extension and then we can restrict to X to 1 of Q of 0 C Well, so we consider extensions of Q-shifts, constant shifts with H on the compact curve and restricting it to extensions over C and the claim is is that the thing is actually that the map is an isomorphism Well, now this helps to define economical pairing on the right hand side for the reason that well we have one corridority for the middle extension to Q well and then certainly we have a map from from the corresponding well we can pass to this which are pure Hodge structures which pair into Q of 0 and then we can pass to well to Hodge cycles inside from Q of 0 to these spaces and then we will get an on degenerate pairing from this and this groups maps to maps to Hodge cycles inside of H1 of C bar with coefficients in H so we have pairing between the corresponding group for H and H star of 1 and so we have the pairing on the corresponding X groups okay so let me write it let me write it down okay now we can use the lemma and just invert the arrows so we have a map from the pairing between X1 of Q of 0 on C and H and the second group will be similar thing for H star of 1 but I prefer to rewrite just passing to dual extensions as X1 between H and Q of 1 and then we have the pairing to Q so again so we used here the lemma in order to pass from the extensions of Hodge local systems on curve to the corresponding extensions between the middle extensions on quantification where you do have the Pankara dialect and this I will call they the nice thing is that there is a way to compute there is a global high pairing but there is a way to compute it using local invariance some local invariance but in order to define this invariance we should have some extra data well the extra data would be a local system E with the following with the following properties so the following extra identification so the weights should be minus 2 minus 1 and 0 and also we should have the identifications of the associated graded quotients this should be Q of 0 this should be H and minus 2 quotient is Q of 1 so now maybe I should I should have said before that suppose that we have 2 elements of the corresponding X groups one is I will call alpha and the second I will call alpha V and my aim is to try to compute to compute the high pairing well now the assumption is that we have this identification such that the corresponding classes of extension of this will be alpha and of that will be alpha V now given such E we can define the local indices maybe let me denote in this manner X and this will be a rational number and they will be defined for every X at the infinity point of C so we consider the complement of C in C bar and then to every point given such an E then I can define a local X so let me let me define well in order to define it I consider let's consider the middle extension now of E to the whole of C bar well maybe even let's do the shift so to make a Y1 so to make our things perverse and let's look how this middle extension would look like well now it's easy to see that so E shifted by 1 now has weight 0 and so the whole thing could have sorry it will E shifted by 1 will have weights 0 plus and minus 1 and the middle extension would look like this so you have the top associated quotient is Q of 0 now the 0 the middle weight quotient the thing looks as follows well so first it is a pure pure shift of weight 0 so it splits and it splits into pieces since it's restriction to C equals equals E then the thing would be just a direct sum of some delta which is supported at C bar skyscraper supported at infinity at C bar minus C and the middle extension of E and then we have the bottom part this is suddenly it's usual so now E of H it was E oh no no no it's H I'm sorry yes you are perfectly right it's H yes yeah well now we can define the number well we know that so we have success of extension so we can consider classes of X1 so we know that classes of Q of 0 by means of H is alpha and here we have class which is alpha E but now we have extension also of Q of 0 by delta by the skyscraper shift and let's call it beta and here we will have beta V well and we can compose them beta and beta V and then we will get a number so for delta is skyscraper at C bar minus C so it's the same as if we do everything at every point and so we get a collection of numbers because well it's composition of 2X1 so it's X2 with support in a point at infinity and this is just Q so and by definition this local index of E at a point at infinity it is just well let's take number with minus sign it is a composition of beta V beta which is again is viewed as X2 with support in X of Q of 0 and Q of 1 and this is a rational number so for every point at infinity we have local index it is essentially immediate that the sum of this well that the sum of this local index equals the high pairing of alpha and alpha E well it's immediate because well here if you just look at this successive extension of W you see that the composition of 2X1 this one which has 2 components alpha and beta and another which have component alpha V and beta V is 0 as element in X2 and this is exactly alpha alpha V and plus beta beta V and so so it's essentially an open assertion so but it is very useful for for the following reason well first the first question is how to find well E this E first the abstraction to the existence of E lies in lies in well if you just look at it it lies in X2 with Q of 0 on C and Q of 1 on C and this is the same as Picard group of C and so shrinking C you can you can find E and also I did not say but I should have said that this high pairing itself it does not depend on if we shrink C we shrink well and locally and different E well it's if we have such sort of a double extension that certainly we have just an extension of Q of 0 by Q of 1 we can consider the bar sum of it with E and we get another E and it's easier to see that this makes all E's a torsor over X1 between Q of 0 and Q of 1 and this is this is just invertible functions on C and well so well if there is one E this will be a torsor so essentially so we have just a torsor with respect to invertible functions standard Q on our Q so this is the data of E and it's easier to see how local the global certainly the global high pairing does not depend on the choice of E and depends on E on E of the local indices certainly if I would just add will translate E by means of of an invertible function F here then the corresponding pairings well this will be the sum of certainly I don't remember the sum but let's take the clues the divisor of F at X so that is the picture well now let me formulate let me explain what the story has to do with algebraic cycles and then I will explain how the theorem comes the geometric version of the theorem comes well suppose that we have let E at high pairing of algebraic cycles suppose that we have let E at be genetic point of C and we have a smooth project variety X E at over E at well and suppose that we have two elements of the Chao groups alpha Chao group of co-dimension I of X E and we have alpha V which is in Chao J of X E and I want that I and J I will be chosen so that I plus J equals well that they would not intersect but just just just a bit so it will be dimension over E plus one so and then and then suppose also that alpha and alpha V are homologically equivalent to 0 on the generic geometric fiber well in this situation can well the previous construction they help to define the pairing of their high pairing and this will be a rational number and in order to define it we should just apply the previous construction to to define we should do the following first spread our X E to project a family over C say P and then let's also spread our cycles and let's define H as the direct image of Q of I minus one of Q of I on X and this will be a local will be a local system and we will have the classes of classes of alpha and alpha V exactly define the elements because alpha and alpha V are homologically equivalent to 0 on every fiber they define the corresponding extension classes we have which will lie in the next one 0 and H same for alpha V and we can just just apply the previous construction so this will be the global high-paying but we also can define local high-paying and well the only procedures that I knew before was that we should pick representatives of alpha and alpha V as true two algebraic cycles and spread it so that the corresponding well the supports of the corresponding cycles over C would not would not intersect and this is possible after shrinking C certainly and then we can define our local system let me just write down just write down its fibers we consider first the local system with fibers let A and B with the closures A and support alpha and B and support of V and again they do not intersect and then we can we can consider the relative group for every fiber we can consider the relative group of B and therefore the local system on our curve and we can use well the thing is not exactly extension by Q0 by Q1 but here will be a linear of 0 power A and here will be Q1 power B and then we should use alpha and alpha V to pull back and push forward to get exactly E in the shape we had before and then we will have local indices this is a nice procedure the only problem of it for example is that really in order to define I think we should have cycles with non-intersecting support and for example computing self-intersection is sort of a problem but now let me explain how you geometric version of the theorem well so we should do just what we did in case of theorem but replacing a rational spectrum of rational numbers which was very base by the generic point of C so basically this means the following that we consider we have our curve and we consider it inside of surface T and these are zeros of a function F well and then we have a family YT over T and this is a project so YT to T the project and I assume that YT is smooth and what I want is and its dimension is 10 plus 1 and what I assume is that all singular point that the singularity of the projection of y over C but actually has a single quadratic singularity so that's our picture well and here we can do just repeat everything that we did in the very beginning we can let then we have Y this singular thing that leaves over C we have a section I which assigns the point of C the only singular point in the fiber and then we can consider the blow up of YC at that point and that will be X well and again the fiber over of X over I is a non-degenerate quadratic so we have yes I want to understand your setup C is a complex curve yes yes what is T? T is the surface T is the surface yes and it lies over well it doesn't lie over okay and C is given by equation F equals to 0 and they are complete no I don't well the projection from Y to T is projected and YT but about T I don't care and I'm interested in it only near C and actually of C I also interested in the generic point of C so the base is not complete at all okay now again I blow I blow up YC at this at the singular point and so I get something X over YC X now and the exceptional divisor is Q will be a family of non-degenerate quadrics over C and I can do the very same thing I can I can define the block cycle I consider the two rulings of the quadrics I consider their difference and then I will get the block cycle P and I will consider it as an element of the middle Chao group of X turns RQ and again let's assume that the condition of the very first lemma holds so that if I consider the homology of non-singular fibers near C then the local monodrome will be non-trivial what were what were the degrees N-1 is non-trivial again then B will be homologically equivalent to zero and we can in this situation as I explained before we can consider the self-heat-paying just a moment so I should just a moment okay well so we can ask what would be the corresponding self-paying and the analog of the theorem is this so we should consider again the local family the local system of homology and so we consider local system E and this will be the vanishings the nearby cycles they will lie over C the local system over C and this will be applied to a local system which is defined on the complement so it will be local system with fibers H2N-1 Y QFN if you will look how it looks like again you have three weights and the successive quotients this will be Q of zero on C and then the next one minus one it will be the intersection of Y0 with k-efficient intersection and again there will be Q1 and this is exactly the data we played of E on a curve we played with and with this we can associate the local indices and we can compute if you wish there are some and the thing is that the corresponding global the claim is that the sum of this local indices is exactly is exactly the self-pairing of BB and the reason for this is just to check it we should just check that the two extensions are corresponded exactly to B and this is maybe let me formulate well I don't have I don't have time but maybe let me just say that what happens in just a few words what happens in the arithmetic situation everything could be done exactly as in geometry except that well for Q we have for spectrum of Z we should consider all points there will be non-archimede points and there will be archimede points and the number we consider is actually the local the analog of EX at non-archimede points but at archimede points we have similar numbers but to define them we have to use a larger chronology the current level of our knowledge as far as understanding is sufficient to know that there are rational numbers but the moment we know that there are rational numbers well we will have both the height-pairing is defined and again the height-pairing is defined also only model of this conjecture of rationality and it will be automatically equal to the corresponding corresponding sound that comes from from the nearby cycles which structure well, that's it so so any questions from Luke very naive question in the local situation so the local pair ability dimension one and one and quadratic singularity and here I take a curve similar to the reduction then in this case is there a relation between this height-pairing this local thing local indices I think and the characteristics theorem and gotendic model in pairing well, in the sense they are different well both the half-layer shots and gotendic monotrabia they are somehow inherently inside of the story for example this leomated algebraic cycles the classes of algebraic cycles homologically equivalent to zero can be extended to x1 for completed curve with intermediate extension of psychology itself it uses you really play with weights here so you should have gotendic monadronic theorem in the definition of this local cycles you also use it and so you use it's just inside but in fact gotendic you eventually arise a quadratic form so you take all the and it was not so easy to find the characteristics so it's quite easily easy so I wonder whether this more geometric approach could give a simpler definition of gotendic monadronic bearing and perhaps cool that it is in fact a perfect bearing maybe to prove integrality well I guess in case of relative dimension one you could prove you could prove integrality these last things that the local indices are actually not play naladic numbers but are rational but in half dimension I just have no idea any other questions so at the end I didn't follow the role of T it doesn't appear so what is the role of T I forgot maybe I was tired so T is the surface in which T is embedded with some kind of thickening so what is the role of T T the role of small T the parameter no no the surface the local monodrome the local monodrome the local monodrome of the family local monodrome or what the local T was also I think denoted the local monodrome of the family on the acting on the homology and that is for some T-1 identified the top weight quotient with a bulletin tape quotient okay so can you formulate the problem in naladic homology and is the result that you mentioned in the beginning does it depend on this rationality you said that the theorem is that something well modulo combination of log of parts is rational coefficients or it depends on some the result depends on some conjecture or not the theorem that I formulated in the beginning no it is not conjectural if you do it modulo modulo this pure linear combinations of logarithms of primes but you could if you know the conjectural rationality then you could you could get actual quality also the high pairing itself it also it is what is the conjectural thing that you okay so let me let me try to say it so we have maybe you can write again okay so let me let me try to do it problem is it tells that it creates all possible whiteboards okay so let me first delete just a moment okay so great now I can well so we have well we have if you wish M i t f over q M i t f e just a moment which is extension of say I don't know q of q of zero and then something called weight minus one say h I don't know and q of one well in the sense of or of nori maybe maybe the sense of nori then you can define for every for every p you can you can try to find abstraction to extending to the whole zp as an extension of q of zero by middle extension of h by q of one the problem is that you don't you don't have you don't have the language well nori motifs they work if you work over field of characteristics zero something like this but you can ask the corresponding eladic question then then they take middle extension and basically repeat all the words and then they get then they get a number and this number will be eladic and this you will get for a given p you will get for all l you will get its eladic numbers but you want it to be actually a rational number independent of l and then you can you can take this rational number with multiplied by log of p and then sum up everything and this will be an archimedeon component which comes from coach theory and then this will be something which depends only on two extensions q of zero by h and h by q of one by q of one by h you don't need well dependence of e disappears on this and this will be what does a global high but it's defined only in case only if you have if you can solve this this problem of rationality otherwise you can with what you considered in the theorem? Yes, with vanishing cycles. Yes, and it's very simple. So you get E, which has exactly as the shape as I wrote, which comes from vanishing cycles. And it's very easy to identify the successive quotients, the two successive quotients that they actually equal to B. And the reason for this, if you wish, is that, well, you have middle extension there. And in middle extension, if you consider on the whole family, there will come middle extension from the complement of singular point of the hyper surface to the whole hyper surface. And this will be primitive cycles on the corresponding quadric. And this is essentially as a plot cycle. So it's this part is simple. But you didn't define, well, I remember that you had a paper in the 80s, I think, but I don't, in any case, you didn't, in your talk, you wrote B, angular bracket B, you didn't say what it is. What is the high pairing of the cycle B with itself is? Yes. What happened in this work was that it was conditional definition of the high pairing model or this conjecture of rationality. So in the theorem, the high pairing of B and B is defined assuming some conjecture, yes? Yes. Yes, itself it is defined as, if you don't assume, it is defined only as element of the quotient of R, model of Q linear combination of logarithms of primes. And this you can do anyway by another method. Yes. OK. OK, I'm sorry for what I'm saying. I have a question from the audience. So Bruno Kahn is asking, is he the realisation of one motif in general? Is there a one motif? No, I think not. Well, it is for a family of curves. But for higher dimension, you will have just something of three consecutive weights. And the middle is not of type, well, 1, 0, 0, 1. But it could be, well, so it's not one motif in the sense of the length, period de Hodge-Trois. So there was a question. So let's thank the speaker again.


Go! The tucpreneur is here. As you can see with the background, I have a lot of books here, right? That tells you that I'm very smart and I know everything that I'm talking about. Okay? So Let's agree on that premise and then listen to my opinion. All right, so the the goal of this video is I would like to share my views on on this book by the laws of human nature by Robert Green and I find it's very interesting book. I'm still reading it and and The reason I find it interesting is Three years ago, I I had a lot of issues. I was very insecure. I was a Was watching to people I was very angry, you know, I was very angry. I was always sabotaging myself So there are there were personal issues that I never knew I had and I also getting conflict with my clients and when I when I read when I read this book, it gave me a perspective it gave me a Clear understanding of my behavior So it it helped me understand that My behavior is not It's coming from a place of Let's say not a stable or it coming from a place of anger and that It helped me to relax basically To take to take it easy instead of getting angry For no reason and sometimes And that you don't know the problem is If you don't know that you have issues, it's very hard to deal with them So I didn't know that that I didn't know exactly that I was a ship. I was a problem and that This book really helped me to understand complex things and to understand my personal personality better and That's why I would like to recommend it. I mean there are a lot of people who Project their insecurities to others And without even knowing it sometimes we are We are acting based on anger based on jealousy based on envy Based on hate, but we don't realize that you know We don't really take you Stand back and think about it When you hate somebody you don't even know that that's actually You hate the person Not based on Anything else, but based on the fact that Based on only on jealousy or envy You don't like the person to be successful So Since we cannot attain his status You start developing hate for that person No, it could be for a company But it could be for any country So this books really gives you a Timeout basically The timeout says you have issues You got a deal of them Now I'm still in the process But when I start reading I was able to come down. I Was able to be to have a little bit of self-control a little bit self-control when it comes to Being angry Okay, a little bit self-control when dealing with clients and it's still in the process, but this is I think This is I think how I'm going to build in a stable in a stable and Rational and behavior So I think there are a lot of people that have similar issues and they will really help you to To cope with these issues that you have Okay, so I will really recommend it and the if you get chance just take it read it It will change you will change your life


I hope everyone is doing good. Today we're going to talk about writing, secure, writing, secure, and correct smart contracts. So in particular, I'm going to talk about some directions and some problems we've been thinking about in academia. And I'll also try to tie it into an industry perspective for those of you who are smart contract practitioners. All right, so let's start out with who is IC3. IC3 is sort of a research hub centered around the universities you see there, mostly Cornell University, also UIC Berkeley, Cornell Tech, and the Technion. We've got 12 faculty at the last count, and we're adding more all the time. In the last month, we've added at least two or three faculty. And we've got many, many students at all levels of education. So before I start, I'd like to give a special thanks to the Ethereum Foundation for inviting us here and putting in all the work to bring us together. And also to our industry partners at Chain Digital Asset and IBM, thank you guys very much for your continued support of smart contract research. We'll also be announcing more partners in the coming weeks. And we'd love to have you guys as a partner. I know there are a lot of companies here who are interested in the correctness and performance of cryptocurrencies, blockchains, and smart contracts. So if that's you, please feel free to check out our website at initc3.org and contact us. All right, so here is the work that IC3 is doing. As far as we see it, there are five grand challenges in smart contract performance. Sorry, smart contracts and cryptocurrencies. One of them is scaling and performance. The second one is correctness. Third one is confidentiality. The fourth one is authenticated data, so getting data sources into these systems. And the last one is safety and compliance, which you've heard a little bit about today. So this talk, I'm gonna be focusing on correctness and its relationship to security and how we write secure and correct smart contracts. So this is intended to be a high level overview. We're not trying to be comprehensive here. There's a lot of work we're not gonna mention. We are also gonna provide some suggestions for practitioners, since there are many of you guys in the room writing smart contracts. And I'm gonna draw frequent parallels to safety critical software, whether they be in planes, cars, power grids, or other infrastructure systems and software like that. All right, so we all know this problem pretty well by now as a community. The problem is you have this software bug. It leads to money being lost or stolen, and then people who write and participate in the smart contracts cry. So there are some things about this challenge that are definitely unique to the cryptocurrency and smart contract ecosystem. One of those is that security is more closely tied to code correctness than anywhere else. So you have this sort of problem that any issue in correctness, which leads to a fault or software bug, may be directly monetizable by an attacker. And these attackers can also anonymously monetize these exploits untraceably. We've also got a unique adversarial environment here. So everything that runs on these systems from the miners to the node network to the actors that participate in the contracts could potentially be adversarial. And if it's not bad enough already, we're looking at public code. So in your car or in an airplane, you don't have access to the code that's running to try to test it for exploits, but on smart contracts, all code is public on the blockchain. All right, so how do we start tackling this pretty difficult problem? As far as we see it, there are three prongs here that will help us sort of stick a fork in this problem of smart contract correctness and security. The first one is formal verification and specification. The second one is escape hatches or otherwise known as kill switches. And the last one is bug bounties. So getting right into it, we're gonna talk about formal verification here. So formal verification is probably the hottest topic of these three in the community right now. There are several talks going on about it at this event and it's a really exciting space to be in. So what do we like about formal verification? Well, first of all, I think specification is a great virtue. So by rigorously and mathematically specifying what you're building, it helps you understand the systems that you're making on a deeper level. Also specifying the lower levels this rigorously, things like the EVM and the languages that we're using helps authors of higher level systems know exactly what guarantees they can expect from these systems. So specifications are great and the more rigorous these specifications are, the better we can start to tackle the problem of writing correct contracts. English specifications are pretty common in the field. These are definitely not enough. They admit ambiguity. You want an example of this? Check out the ISO C11 standard, which has a whole committee whose job it is to argue about whether certain programs do or do not conform to the standard. Formal specifications can also go further in serving as criteria for forks. So the question of when to fork these systems could be answered by when the implementation of the system differs from its specification, in which case you have a very clear bug. Obviously, specifications also give you these other side benefits. They can help us find bugs and they can help us generate tools that we use to analyze our contracts. All right, so let's talk a little bit about the work that's being done here. Both of these slides are gonna have later talks on them, so I'll be brief. One of them is this tool called Oyente out of the University of Singapore, I believe. And what they did is they took the semantics of the EVM that was very nicely laid out in the Ethereum yellow paper, which I think is an excellent document and a great way to sort of set the standard for the rigor that we expect from these systems. And they built some tools on top of it to analyze the blockchain to try to discover bugs in smart contracts running in the wild. So I highly suggest you read the paper. I love the work that this team did. I think it's not perfect. I do think that there are many false positives that sort of come with their approach that we can further refine and get rid of as these tools evolve. So if you wanna talk more about this work, you can ask questions at the presentation that's coming up later in the event, or you can find me afterwards. All right, here is another great example. Dr. Christian Wright-Wiesner, I hope I pronounced that right, with a Y3 sort of backend for formal verification in Solidity. So here you can see a very simple funds contract and a specification over this contract that was presented at the IC3 Ethereum bootcamp earlier. And this contract allows you to withdraw a certain amount of shares and comes with the specification that the number of shares preserves the balance of the contract. So oops, that was the wrong direction. So here is another contract that satisfies this specification. And this sort of helps us illustrate that writing complete specifications is pretty difficult.  Now this is not intended to say that this work was intended to catch these sort of cases. This is obviously a trivial example. But the general point is anywhere you look in the formal verification space, writing these specifications is extremely difficult. So the gaps in this work, specification is hard. Some properties can't be specified at all. I'm thinking specifically about properties of incentives, game theoretical properties, and higher level properties of smart contracts that are pretty much impossible to specify. Often when you have a proof of these kinds of things, you are trusting the tools that outputted the proof, which is not an ideal situation, because these tools are very hard to audit and they require significant expertise. We don't even really know how to audit them in general. A key takeaway I'd like you to get from this is that any good tool must use some sort of semantics, that is a definition of the lower levels of the language and the infrastructure on which they operate. So when you're trying to evaluate one of these tools, ask yourself, what semantics are they using? How is it audited and what guarantees do we have that that system will actually conform to those semantics? Right now, to really formally verify complex systems, we need experts, we need multiple PhDs. It's not an easy problem. And there are also some famous incompleteness and undecidability results that may suggest that gaps in these logics could require more work to achieve a robust system. All right, so escape hatches. This comes out of the need of not always being able to verify our contracts. So what we need here is something they figured out very early on in safety-critical systems, which is we need to put a human in the loop at some point. It's true that the promise of these systems involves, in many cases, taking the humans out of the loop, and I think in many cases that can be achieved, but we shouldn't necessarily take that as an absolute. If verification or bounties or the other two prongs of the approaches fail, it's important to have some sort of fail-safer backup mechanism. There are a lot of parallels to legacy contract law here, so there are a lot of lessons to be learned from how people have done this previously in contracts and also parallels to safety-critical systems. So I'll pose the question to the audience, would you write a nuclear power plant software that has no kill switch in it? Probably not, and I wouldn't want a multi-hundred million dollar contract not to have one either. So we've been doing some work on this in IC3 by Bill Marino here. I highly suggest you read the paper for more information since I don't have much time to discuss it. And what we did here, Bill was a lawyer by trade and got a master's in computer science and he looked at parallels between smart contracts and legacy contract laws. So he looked at all of these concepts of termination, rescission, and modification that are codified in the law that have been designed to solve problems that have come up in historical precedence. And he wrote little Ethereum libraries sort of mirroring these concepts in traditional contract law. So if you're writing a high-value smart contract, I highly suggest you take a look. So this is again not problem-free. We've got a bunch of gaps in this approach. How do we verify that the escape hatch code is correct? What layer do we put the escape hatches in? Do we want escape hatches in the EVM, which would inherently be sort of less general since you'd have a specific set of hatches? Or do we want to put them in the compiler, which lets us save some generality by deferring the problem to the language? Or do we want to just say contracts, use well-audited libraries of escape hatches that you can modify as you see fit, giving us that full generality? So it's an open question. There's also a lot of potential for abuse in escape hatches. So a bad actor could perhaps trigger an escape hatch in a case where it's profitable for them even if it doesn't follow the intent of the escape hatch. That's something we always sort of need to keep in mind. So can you think of a badly made escape hatch? There have definitely been contracts before that have intended to provide a mechanism for users to remove funds that have then been abused to drain all of the funds out of the system. I won't mention specifics, but it's online 666 of the contract that I'm talking about. It's also worth noting that forks of the system in general can be viewed as an escape hatch. Whenever there is a catastrophic failure involving multiple aspects of the system, you sort of get the social consensus-based escape hatch that comes with the backend architecture of these systems. All right, the last prong of our three prong fork, bug bounties. So we believe bug bounties are very important because the incentivization structure of developing exploits is pretty broken without bounties. So what do we mean by this? In security, traditionally we say it's never impossible to exploit a system. It can only be expensive. And when you have a cost of exploiting a system that's actually much lower than the amount that's to be gained from exploiting it, an exploit and an attack will pretty much inevitably surface. So in order to fix these sort of issues, the general security community has recognized the value of providing bounties to incentivize people to defend the system financially rather than only financially incentivizing attackers. Without them, defenders are really only motivated by ego or maybe goodwill, which, as we've seen in the past, are not really powerful motivators to do the type of work that's required for a full security audit. So the good about bug bounties, we have the poor man's formal verification or as we like to call it, decentralized censorship resistant, anti-fragile incentive compatible crowdsourced verification. You can tell that one to your managers and I'm sure they'll be glad to fund your escape hatch development. All right, so we got some cool work going on in this space. Some of my favorite work is the idea of using these prediction markets that we're developing as sort of canaries for when an exploit is about to happen because attackers will naturally be incentivized to reveal this by taking a position on the prediction markets in that direction. So that's sort of the more fringe work that's going on. We also have work that directly addresses these issues in a more traditional way. So there's a blog post by Simone de la Riviere. Again, I hope I'm pronouncing that right. On Medium called Asset Guards, which I highly suggest you take a look at, that details one potential approach for escape hatches. There's also escape hatches mentioned in the Ethereum, best practices for smart contracts documentation. And there's a user called ThouChallenge on Medium who's posted a series of really small contracts that contain common patterns and asked the community to try to break these contracts in order to reveal underlying language flaws or issues in our coding practices that we haven't really yet thought of. There's a lot more work going on in this space. If you Google escape, sorry, bug bounties, Ethereum, bug bounty smart contracts, you'll come up with a ton of stuff. So there's a common problem in academia and in general that you have all of these great solutions to the escape hatch problem and all these great proposals and you consider the problem solved. And I would urge you guys to avoid that line of thinking because there are still gaps in this bug bounty approach. So with prediction markets, there's always the question of how to avoid bad incentives and how to prevent incentivizing attackers and bad actors from actually deploying their attacks on the main net and profiting. There's also the hard problem of how to create trustless bounties with trustless payout. We don't wanna leak these exploits to the testnet because once you leak the exploit to the testnet, you've removed the incentive for defenders and attackers can take that exploit and deploy it on the main net. We also don't want to trust contract authors to pay out because that significantly harms the attacker's incentive to report the bug if they think it's a really profitable bug and the contract authors may just invoke a kill switch or fix it before they have the chance to get paid. There's also the very, very hard problem of how do we define conditions for bug bounties? How do we know when an exploit is a valid claim of a bounty?  We have a paper about that on our website that basically involves using trusted hardware to deliver a proof of an exploit without revealing the exploit itself. SGX also leverages trusted hardware. Maybe zero knowledge proofs could be useful here, et cetera. Bug bounties are also hard to do for subtle issues, things that I talked about before, game theoretical issues or fundamental flaws in the architecture of your contracts. So like our other two prongs, they're not a silver bullet. Also, I urge you not to forget traditional software engineering tests, buzzing, static dynamic analysis, phase deployment, upgrades, smaller test contracts. These are all very valuable things. I don't think I need to talk about them. Pretty obvious how to use them and I highly suggest you cover all of these bases if you're writing a high-value contract. All right, so takeaways. We've got lots of work still to do here. The ecosystem definitely will develop good formal tools. We have a number of talks on this. Think about humans in the loops when you're writing your smart contracts and use bug bounties as a stop gap for verification and incentive fixes. Thank you guys for listening and if you want to interact with us further, please check out our website at initc3.org. Check out our publications and we are always looking for industry collaborations and partners. We'd love to work with you to solve the open research problems in the space. So definitely contact us or find me somewhere if you have questions about anything I've said here. All right, thank you very much. Thank you.


What's up everybody, I'm the Mangus, you were awesome, and today I'm playing a bit of Heroes of the Storm, Blizzard's MOBA brawler that takes advantage of all their IPs like Warcraft, Starcraft, Overwatch, and Diablo. Even though this was my first MOBA-ish game, I always forget it exists and that I'm actually kinda good at it. I'll go through today and try to explain what HOTS is all about. I'm playing my favorite hero, Kerrigan, from the Starcraft universe, and I'm using the Succubus skin because of, uh, reasons. Let's run through our abilities real quick. Her passive gives you shields whenever you deal damage. Her Q, Ravage, has two charges and lets you leap to an enemy and deal damage.  Her W, Impaling Blades, lets you put down a little AoE that shoots up blades after a delay that stuns targets.  So what you want to do is place Impaling Blades, then pull enemies into the stun and keep them in range for the explosion. Most heroes in Heroes of the Storm have two ultimates to choose from. Kerrigan's first is Maelstrom, and that's like a constant AoE around you. The second one is summon Ultra Lisk. You summon a little buddy that will charge forward and stun a target. You can then direct him to attack whatever you want.  You do have to, once you hit level 10, you unlock your ultimate, your choice of ultimates I should say, and they don't have an item shop. What they do have is you get to pick talents at various levels, 1, 4, 7, 10, 13, 16, 20. Whenever you get to those levels, you get to unlock talents that will help you in the game. For this one, my level 1 talent, I picked up Siphoning Impact, which gives me extra shielding whenever I ravage somebody, because the enemy team has a lot of assassins and I'm really the only front line, so whenever I dive in, I want that extra shielding to sustain me. Another thing about Heroes, it always starts off with both teams kind of dancing around the middle lane, and then eventually everybody splits off and goes to different lanes because there's shared experience. Whenever you kill the minions, they drop a little ball on the ground, kind of like how it used to be in Paragon, where the CXP would drop on the ground and you would have to go pick it up, so you can deny people from getting their experience, but it's shared amongst the team, so there's no gold, just experience, and that kind of ensures that everybody stays, like everybody covers down a lane, so that you get as much XP as possible for your team, and you're going to watch me kind of... I'm going to be up against a Zagara in the bottom lane. Zagara is a bit of a lane bully, but I ended up bullying her quite a bit and denying her from getting XP while getting XP for myself, and yeah, I missed that combo right there, and yeah, it puts our team way ahead. I didn't have quite enough oomph to finish that kill, but that's fine. Again, it's going to drive her away from getting XP, she's going to be a little bit scared of me, and that's another thing. Almost everybody will use Ravage to get close and then use the combo to prevent people from earning away. You can just throw the combo naked and get them a lot of the time.  I normally don't take this talent because it's hard to stack up, but I'd already invested in the Ravage talent at level one, so I figured I would go ahead and just keep going down the Ravage path, caught her with another naked combo. Again, I don't really care if I kill her or not, as long as I push her out of lane and get the XP. As you can see, we're level five, their team's level four. We're already starting to get a pretty good XP advantage. Another thing about Heroes of the Storm is you have different maps with different map objectives. For this one, you have nukes that spawn across the map, and you can collect them and then use them on your enemies, well, you could use them wherever you want to, but usually you would use them on the enemy structures. Caught Genji with a naked stun there. That's another thing a lot of characters tend to forget that they can do. You don't have to combo every time. You can just throw the stun down when somebody's chasing you, you can often catch them with it and prevent the chase. He's trying to come down here and steal my nuke. If they kill me, that nuke drops and they can collect it and use it on my towers. Got another Q talent for Ravage. This one's going to give me an extra charge of it. That's pretty much it. And there's the nuke I was talking about. We just hit level 10, which means we unlocked our ultimate. And a lot of it is due to what I've been doing to this Zagara down here. I've just been collecting a ton of XP for our team. Ooh, the stats there. Yeah, I have the highest, but I do have a lot. And a big combo wipes out the thrall. Almost. Yeah, I did get both of them, my little buddy. I got the Zagara and then my little buddy got picked up to kill him the thrall. Another interesting thing about here is the storm. Whenever you take a jungle camp, this is a jungle camp that I'm taking right now, they work for you. They convert over to your team and march down the lane and push. And there's different types of mercenary camps on different maps. So that's kind of cool. Taking advantage of the resets on my Q because I was getting kills with the Q. I was getting a reset, which allowed me to just keep hopping around and blasting people. Another interesting thing about this particular map, you got a sewer system that lets you teleport from bot lane to the top lane real quick. You can surprise people like this for Zagara. And it doesn't really matter that she definitely stole my kill there. That doesn't really matter because, again, it's shared XP. It would have been nice to get the stacks for my Rabbage Quest, but you know what, oh well. Two things I completely neglected to mention.   And then there's a healing fountain next to the fort. The healing fountain is now invulnerable. I didn't even know this till I was playing again. And yeah, you could just, it's on, I think a minute and a half cooldown and you could just tap it for extra health and mana. But it does get destroyed whenever you take down a fort.  I could've had all of them before to use my Ultra Lisk a little bit sooner. And this is, the enemy took a camp and that's what we're trying to clear out right now. That's their camp. That's why there's way bigger minions amongst those minions, as their camp pushing down the lane. But we have, since we took down a fort, we have catapult minions with us. That's the big cannon mortar looking thing in the back. And my Rabbage Quest is finished. I think that's the fastest I've ever finished that quest, nine and a half minutes. And that just gives me just even more damage on my Ravage, so I'm just smacking them even harder now. The team really wanted me to initiate right here, but I gotta wait until one of them steps out of position. I, I wanna wait for them to make a mistake before I dive in, because that is a lot of minions. That's a lot of enemies and there's a, there's an inhibitor right there. And boom, Genji just stepped out of position. They stepped up. And now we got him. Now we got him. Oh my God. Unfortunately, he had his dash up, so I wasn't able to kill him as well. Another interesting thing about here is the storm. Each map has a different core that has different abilities. The map, the core on this ability, you probably saw the big blue circle there that was the core firing its own nukes. So that core fires big AOE damage. Not all of them do that. Some of them have like a pushback mechanic. It's just each map has a different core that has different abilities. I think that's really cool. I think this whole, there's a lot of really cool concepts within here's of the storm. Oh yeah. As I'm watching this, the other thing, you have mounts in here as the storm, so you can mount up to go a little faster. If you get hit, it just takes you off the mount and you get your normal movement speed. It doesn't root you or stun you or anything. Got another, got another talent. I think I forgot the, what I, what I picked up my 13 talent, but I picked up, it's a talent that gives you extra shields, but they don't last as long. So it just better burst shielding, better burst healing, I guess you would call it. And then I picked up a talent that gives me extra damage on my stun for my level 16 talent. I don't even know, I don't even remember. Got her. Got her good. I don't even remember if we even made it to level 20, but that's when you get your storm talents, which normally on Kerrigan, you can get a blank on her and that's what I normally take with her. But I don't, I don't even know if we hit 20 here and down goes their core that's, that's here's the storm for you. It's the first mobile I ever played really. Well, I think I actually played Dota before this is the first mobile I got into. So this is kind of what led me into getting into Paragon. It's what, what's what perked my interest in Paragon on a, yeah, they got that, they got MVP for taking my kill. That's what they got the MVP for, but yeah, pretty good game, pretty fun one.  So we can play some hot man go special shout out to channel members foolish blood hunter jelly knees me I'll mix for men stunt Farith and Raven.


Hello children it's story time again. Today before reading the book I thought I will teach you something new. Do you know just the way we have different body parts? A book also have different parts? Today we will talk about different parts of the book. So here I have a book. Yes what you see here is the front cover of the book. What you see here is the front cover of the book. We always open a book from the front and we read a book from the front. This is the back cover of the book or this is the back side of the book. Now what you see here is the middle of the book. What you see here is the middle of the book and this is called spine. This is called spine. The spine of the book helps to keep all the pages together. The spine of the book holds all the pages of the book together. Now what do you see on the front of the book? The front of the book tells us about what is inside the book. What is the story all about? What do you see here? I see a big dog. Isn't that dog very big and do you see a boy and a girl? Are they big or are they small? They are small and the dog is big. What is the color of the dog? Yes it's a red dog with a black nose. So this story is about this big red dog. Now what you see here is the title of the book that is the name of this book. So the name or the title of this book is Clifford's Good Deeds. So the name or the title of this book is Clifford's Good Deeds. What else would you see on the front cover of the book? You also see another name here. It says Norman Bridwell. So who is Norman Bridwell? Norman Bridwell is the author of the book. Now you must be wondering who is an author? An author is a person who writes the story, who writes the book. Okay so many a times you will see author of the book is and the name of the author you may also see written by in the name of the author. Now do you see this beautiful picture of the dog here? Yes now this is also called as illustration and you know the person who makes all these beautiful drawings or create the picture for the story or the book. The person is called an illustrator. What is that person called? Illustrator. Now many a times the illustrator and the author may be the same person which means the same person wrote the story in the same person made the pictures for the book. Now what I will do is I will show you another book and you have to name the different parts of the book. Okay I will just open the book for you. So what do you see here? You see two pictures right one and two. So what do you see here? What is this? This is the front of the book. It's called the front side of the book or it's called the front cover of the book. What is this? That's right this is the back cover of the book. This is the back cover of the book. Now what is this? I know this is the front of the book. This is the back of the book. What is this? It is the spine of the book. The middle of the book that holds all the pages together. Now in the front of the book I see something written out here. What is this? Yes that's the title the name of the book or the story and the name of this book is the golden fish. Do you see a beautiful fish out here? A golden fish? I also see that it says written by Teresa Green. What does this mean? Who is Teresa Green? She is the author. She is the one who wrote the words in this book or the story. So she wrote the story the golden fish. This says pictures by Brenda Lee. Pictures by Brenda Lee. So who is Brenda Lee? Brenda Lee is the illustrator. So she is the one who made this beautiful fish. The picture of this fish was created by the illustrator Brenda Lee. So now we all know what are the different parts of the book. We will now read a book. The title of this book is Pink is for Boys. The author is Rob Perlman in Who is an Author? An author is the person who writes the story. It's illustrated by Ida Kaban. Who is an illustrator? The person who creates the picture for the story. So let's start reading. Pink is for boys and girls and bows on fancy clothes. Blue is for girls and boys and uniforms on a team. Yellow is for boys and girls and a crown to wear. Green is for girls and boys and grass to run on. Red is for boys and girls and cars racing along the track. Orange is for girls and boys and popsicle through playing down sticky chins. Purple is for boys and girls and unicorns because unicorns. Brown is for girls and boys and teddy bears to cuddle. Black and white are for boys and girls and puppies and kittens to pet. And all the colors are for everyone girls and boys and flowers and butterflies and rainbow in the sky. This book tells us that colors are for everyone. You can wear any color or play any games you like. No matter what's your favorite color or your favorite game, children always remember you are special and I have a very special song for you. I want everyone of you to sing along and enjoy this song. I hope you enjoyed the reading session today. I will see you next time with a new book to read. Until then, happy reading, happy learning. I'll see you soon. Bye-bye.


This is list podcast number six, How to Evaluate Information on the Web, by Emma Tajinski. For further details go to www.cumbria.ac.uk-list. This podcast looks at evaluating information on the web and examine some of the ways in which you can determine the quality and usefulness of a website. There is a huge amount of information on the web, but not all of it is trustworthy or suitable for academic use. In fact, only 6% of information on the web has been designed for educational purposes, so you need to be very careful when looking for websites to use in your studies. It is very important that you evaluate the information you find online before using it. Library resources are likely to have been quality checked at least twice before being made available to you, firstly by the editor or publisher and secondly by the lecturer or librarian who decided that it was suitable for the university's collection. On the internet however, no quality checks are required. Anybody can publish anything on the web, so it is up to you to decide whether or not to trust the information on offer. There are a number of checks that you can do to find out if a website is trustworthy. Firstly, use the domain name to get an idea of the type of site you are looking at. Sites with .com and .co in the address are commercial sites. Some of these sites may be useful, but you need to treat them with caution as they may have been created for advertising or promotional purposes. Sites with .org in the address are owned by non-profit organisations. Again, these could be useful, but they are sometimes biased towards a particular view, so you need to use your judgement and evaluate them thoroughly. Sites with .ac in the address are UK academic sites and those with .edu are American educational sites. The standard of information on these is likely to be high, but you will still need to check that they are appropriate to your level of study before using them, as they could have been developed for schools rather than universities. Sites with .gov in the address are UK government sites, while doh.gov.uk and nhs.uk are UK health sites. If a site is a personal web page, it may contain the name of a blogging tool or personal publishing platform, for example blogspot.com or wordpress.com. You will need to evaluate these sites very carefully before using them, as they are probably not intended to be used for academic purposes. They can also be published by anybody with a computer and access to the internet, so may contain poor quality, false or misleading information. You should also ask yourself what you feel about the overall presentation and content of the site. You can often get an idea of quality by scanning through the information and getting an initial impression of the type of site you are looking at. If the site seems relevant, ask yourself the following questions. Is it accredited by a reputable organisation? Not all trustworthy websites are, but some will be and these are likely to contain good quality information. Look for logos, about those pages and mission statements to find out. Who is the website aimed at and why? Check the help or about this site if you are unsure. How current is the website? Check when it was last updated or if this information is not available. Check whether or not the links are still active. Websites that are not frequently updated may contain out-of-date information, so proceed with caution. How authoritative is the person or organisation responsible for the site? Check whether there is a contact email address and whether the author has written anything else on a similar topic. Also, check to see whether the website refers to other credible sources to back up its arguments. If what is written is supported by references or citations, it is likely to be of a higher standard than if it is purely opinion based. How detailed is the information and is it at the right level? As with all information, you need to make sure that it is suitable for academic use and that it is appropriate to your level of study. As you work through these checks, you should always ask yourself how accurate the information seems. Use what you already know about the subject to make an informed decision and cross-reference some of the details you are unsure of with other sources such as textbooks. One way of finding good quality websites that have already been assessed for relevance is by using a searchable directory such as Intude. This is an online resource which provides links to websites for your subject. All of these have already been checked and evaluated by specialists in the field, so you might find it helpful to use these as a starting point when searching for information. Help and guidance on using Intude is available on the list website along with tutorials showing you how to track down the best websites for your subject. There is also a link to a website evaluation checklist attached to this podcast. You may find it useful to print this out and use it to remind you of what to look for as you search for information online. For further details on this podcast and to listen to others in the series, please visit www.cumbria.ac.uk-liss.