- Видео 466
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Richard E Borcherds
США
Добавлен 9 апр 2020
This is mostly mathematics lectures for graduate courses on algebraic geometry, commutative algebra, and group/rings fields. There are also a few math talks at an undergraduate or high school level and a few short courses on other topics such as complex analysis, theory of numbers, modular forms, category theory, representation theory.
For the current list of courses, see the playlists page for this channel.
For anyone who wants to copy the format of the lectures, I'm using a program called OBS studio with a logitech webcam and a document camera and a yeti microphone. I use sketchpad for the thumbnails.
For the current list of courses, see the playlists page for this channel.
For anyone who wants to copy the format of the lectures, I'm using a program called OBS studio with a logitech webcam and a document camera and a yeti microphone. I use sketchpad for the thumbnails.
Representations of GL2
This lecture is an overview of the complex representations of the group GL2(F), for various fields F.
Просмотров: 8 239
Видео
Mordell-Weil theorem
Просмотров 10 тыс.7 месяцев назад
This lecture sketches the proof of the Mordell Weil theorem, showing that the group of rational points on an elliptic curve or abelian variety is finitely generated.
Selberg trace formula
Просмотров 7 тыс.7 месяцев назад
This lecture gives an overview of the Selberg trace formula for SL_2(R).
Riemann mapping theorem
Просмотров 11 тыс.8 месяцев назад
The Riemann mapping theorem says that any proper simply connected open subset of the complex plane is isomorphic to the open unit disk. This lecture will sketch a proof of it.
Vinberg lecture part 4. Automorphic forms
Просмотров 2,7 тыс.9 месяцев назад
This lecture is part of a series which gives an expanded version of the Vinberg lecture on "Vinberg's algorithm and Kac-Moody algebras". This video is part 4 and describes the relation between hyperbolic reflection groups and automorphic forms. In the problems at the end I forgot to mention the problem of relating Bugaenko's cocompact reflection groups to automorphic forms. The paper by Sun, Wa...
Vinberg lecture part 3. Kac-Moody algebras
Просмотров 3 тыс.9 месяцев назад
This lecture is part of a series which gives an expanded version of the Vinberg lecture on "Vinberg's algorithm and Kac-Moody algebras". This video is part 3 and describes how to associate Lie algebras to some hyperbolic reflection groups. The original version of the Vinberg lecture is here: amathr.org/Borcherds-vinberg/ For the other lectures see ruclips.net/p/PL8yHsr3EFj50MVfqGTj4VF3CBS-bJeal3
Vinberg lecture part 2. The reflection group of II25,1
Просмотров 2,9 тыс.9 месяцев назад
This lecture is part of a series which gives an expanded version of the Vinberg lecture on "Vinberg's algorithm and Kac-Moody algebras". This video is part 2 and describes Conway and Sloane's interpretation of Vinberg's results Belolipetsky's survey paper is here arxiv.org/abs/1506.03111 Vinberg's paper can be found at mathweb.tifr.res.in/sites/default/files/publications/studies/SM_07.pdf The o...
Vinberg lecture part 1.Vinberg's algorithm
Просмотров 9 тыс.9 месяцев назад
This lecture is part of a series which gives an expanded version of the Vinberg lecture on "Vinberg's algorithm and Kac-Moody algebras". This video is part 1 and describes how Vinberg used his algorithm to calculate the reflection groups of some Lorentzian lattices. Vinberg's paper can be found at mathweb.tifr.res.in/sites/default/files/publications/studies/SM_07.pdf The original version of the...
Elliptic functions lecture 4. The sigma function
Просмотров 4,3 тыс.9 месяцев назад
This lecture is part of a series of lectures on elliptic functions. It covers the sigma function, the simplest theta function, and discusses line bundles over C/L. For the other lectures in the course see ruclips.net/p/PL8yHsr3EFj50t6hrPaJ0GruNrN-xPcFTI
Borwein integrals
Просмотров 11 тыс.9 месяцев назад
This lecture is about the strange properties of Borwein integrals. For more details about them see www.ams.org/notices/200505/fea-borwein.pdf
Elliptic functions lecture 3. Jacobi functions
Просмотров 4,8 тыс.9 месяцев назад
This lecture is part of a series of lectures on elliptic functions. We describe the Jacobi functions sn, cn, dn, and show how to view them as sections of order 2 line bundles. For the other lectures in the course see ruclips.net/p/PL8yHsr3EFj50t6hrPaJ0GruNrN-xPcFTI
Elliptic functions lecture 2
Просмотров 7 тыс.9 месяцев назад
This lecture is part of a series of lectures on elliptic functions. This lecture discusses the addition formula for the Weierstrass P function For the other lectures in the course see ruclips.net/p/PL8yHsr3EFj50t6hrPaJ0GruNrN-xPcFTI
Elliptic functions 1. Weierstrass function.
Просмотров 30 тыс.9 месяцев назад
This lecture is part of a series of lectures on Elliptic functions This lecture covers the basic properties of the Weierstrass P function The pictures of elliptic functions in the video come from the book by Jahnke and Emde, which can be found here: archive.org/details/in.ernet.dli.2015.212842 For the other lectures in the course see ruclips.net/p/PL8yHsr3EFj50t6hrPaJ0GruNrN-xPcFTI
Introduction to number theory lecture 53. Three calculators for number theorists
Просмотров 18 тыс.2 года назад
This lecture is part of my Berkeley math 115 course "Introduction to number theory" For the other lectures in the course see ruclips.net/p/PL8yHsr3EFj53L8sMbzIhhXSAOpuZ1Fov8 We discuss some of the number theory features in 3 pocket calculators: the Casio fx-300ES PLUS, the SwissMicros DM42, and the HP 50g. The free simulator for the DM42 can be downloaded from thomasokken.com/free42/ The textbo...
Introduction to number theory lecture 52. Nonvanishing of L series at s=1.
Просмотров 7 тыс.2 года назад
This lecture is part of my Berkeley math 115 course "Introduction to number theory" For the other lectures in the course see ruclips.net/p/PL8yHsr3EFj53L8sMbzIhhXSAOpuZ1Fov8 We sketch how to show that Dirichlet L functions do not vanish at s=1, completing the proof of Dirichlet's theorem. The textbook is "An introduction to the theory of numbers" by Niven, Zuckerman, and Montgomery (5th edition).
Introduction to number theory lecture 51. Proof of Dirichlet's theorem
Просмотров 9 тыс.2 года назад
Introduction to number theory lecture 51. Proof of Dirichlet's theorem
Introduction to number theory lecture 50. Dirichlet characters
Просмотров 7 тыс.2 года назад
Introduction to number theory lecture 50. Dirichlet characters
Introduction to number theory lecture 49. Dirichlet's theorem
Просмотров 9 тыс.2 года назад
Introduction to number theory lecture 49. Dirichlet's theorem
Introduction to number theory lecture 48 Proof of the prime number theorem
Просмотров 10 тыс.2 года назад
Introduction to number theory lecture 48 Proof of the prime number theorem
Introduction to number theory lecture 47. The prime number theorem
Просмотров 8 тыс.2 года назад
Introduction to number theory lecture 47. The prime number theorem
Introduction to number theory lecture 46. Products of Dirichlet series
Просмотров 3,7 тыс.2 года назад
Introduction to number theory lecture 46. Products of Dirichlet series
Introduction to number theory lecture 45 Dirichlet series
Просмотров 6 тыс.2 года назад
Introduction to number theory lecture 45 Dirichlet series
Introduction to number theory lecture 44 Pythagorean triangles
Просмотров 6 тыс.2 года назад
Introduction to number theory lecture 44 Pythagorean triangles
Introduction to number theory lecture 43 Gaussian integers
Просмотров 5 тыс.2 года назад
Introduction to number theory lecture 43 Gaussian integers
Introduction to number theory lecture 42. Examples of indefinite binary quadratic forms.
Просмотров 2,6 тыс.2 года назад
Introduction to number theory lecture 42. Examples of indefinite binary quadratic forms.
Introduction to number theory lecture 41: More examples of binary quadratic forms
Просмотров 2,6 тыс.2 года назад
Introduction to number theory lecture 41: More examples of binary quadratic forms
Introduction to number theory lecture 40. Examples of positive definite forms
Просмотров 3,2 тыс.2 года назад
Introduction to number theory lecture 40. Examples of positive definite forms
Introduction to number theory lecture 39: Equivalence of binary quadratic forms
Просмотров 4,2 тыс.2 года назад
Introduction to number theory lecture 39: Equivalence of binary quadratic forms
Introduction to number theory lecture 38. Binary quadratic forms
Просмотров 5 тыс.2 года назад
Introduction to number theory lecture 38. Binary quadratic forms
Introduction to number theory lecture 37 Continued fractions
Просмотров 7 тыс.2 года назад
Introduction to number theory lecture 37 Continued fractions
"... and probably won't make a lot of sense unless you've seen most of the earlier talks. In fact, frankly, it may well not make much sense even if you have seen the other talks" lol love it
It's just great! With new claims from Google, revisiting this short talk feels really good
30:35 very Fermatian
why you choose those numbers for cover page of your channel ? why you select this diagram as your channel logo ?
The section about crackpots constantly sending proofs of Riemann hypothesis is the best.
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This information is very helpful and valuable. Thank you!
Physics have more math than math in pg level
Thanks for doing this!
This is the highest production video of yours I’ve seen so far, very nice
You are trying the Birch Swinnerton or RH I am sure. Had it been not RH, you might not have kept it a secret.
Thank you so much for your content, you have an incredibily captivating way of presenting things
4π^2 All prime products are 4π^2= [4π^2]^(8/8)= ⇔ [4π^2]^8 × [4π^2]^(1/8) E8 ÷ E8=1 (E8)^24 ×(E8)^(1/24) 3×8=24 The 3rd generation of quark・lepton And it gives a hint to the ABC problem❗️
That was awesome proof and very easy to understand thanks a lot
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If 2x+1 is not divisible by three then 2x+1 is a prime number
Great lecture, thank you.
Do you have an explanation of the key claim at 14:10 - that the string of p elements can’t repeat in <p rotations.
e^π +ie^πi +je^πj +ke^πk +le^πl =MC ^2 e^πi-1=0 jkl=0 Quarternion Octonion Principle of the constancy of the speed of light Law of conservation of energy Law of conservation of momentum ζ(s),η(s),Γ(s) The infinite sum of natural numbers is ∞, -1/12 Differential calculus, integral calculus
supplement Supplementary Note The symbol on the left side of e^π is easily misunderstood. The left side is the identity element. The units are [1], [i], [j], [k], and [l], used for the directional vector of the tangent to the circumference of e^π. Each is a coordinate axis of the coordinate system of the unit circle in the corresponding space. The directional vector of the coordinate axis can be orthogonal, oblique, parallel, intersecting, non-intersecting, or contracting. Please note ⚠️
π= 3.141592653589793…, π≒√2+√3= 3.146264369941972…, This gives some hints. SU(2) → √1√2 U(1) → √1 Next, if we write it in this form √1√[√2+√3]√4 → 2√1√[√2+√3]→2√π √2+√3≡√5 If there are some special spaces where this relationship holds, √2+√3=√5 √5= √2+√3 √7=2×√2+√3=√1+2×√3 √11=√1+2×√5=2×√2+√7 √13=2×√5+√3 √17=√13+2×√2 √19=2×√7+√5=√9+√10 ...=... -∞<...<-4<-3<-2<-1<0<1<2<3<4<5<7<8<9<10<11<12<13<14<15<16<17<18<19<...<+∞ These are true in a space with many one-dimensional lines, which at first glance appear to form triangles and intersect at three-dimensional angles. Each line has an origin 0, and the distance from the origin 0 is 1 unit. The axis of the one-dimensional real part that constitutes the Cartesian coordinate system and the oblique coordinate system has an origin 0 and a unit 1. When you look up at the night sky, the stars shine like the moon, galaxies, and constellations in the sky, and numbers are scattered like shooting stars that suddenly shine brightly.
Can't believe you slandered potatoes. Shameful.
6:40 all groups of order 6 are solvable, but not simple, so I assume it's S₃ 8:00 the eigenvalue gives the left column, not the bottom row
solved. P=peneka. NP=nau-peneka. next...
Absolute life saver!!
7:10 In the example of the construction of "a" splitting field of p(x) = x^3-2 over Q, the field of rational numbers, we factor p(x) = x^3-2 = (x-2^{1/3})(x^2 + 2^{1/3} x + 2^{2/3}) = p_1(x)p_2(x), so that p_2(x) is just irreducible over the field L = Q(2^{1/3}) not over the Q. this irreduciblity over L = Q(2^{1/3}) leads us to the new field M := L [x]/p_2(x) 8:12. 13:33 In the general construction of the fields, i.e., the proof of the existence theorem of the splittiing field of any polynomial p(x) over the field K 13:33, we factor p(x) = p_1(x)p_2(x) .... so that each p_i(x) is irreducible over K but ... as in the example 7:10 should we assume that each p_i(x) is irreducible over K_i, not just K, where K_i is defined by the recursive manner K_{i+1} = K_i[x]/(p_i(x)), and each K_i would be a field if we assumed that each p_i(x) was irreducible over K_i, not K. Or I am not sure but is each p_i(x) automatically irreducible over K_i, if we assume that each p_i(x) irreducible over K???
Thank you very much for these very insightful videos. I appreciate the clarity and lucidness of your presentation. You never sacrifice those in favor of "formal rigor". I am wondering if you could cover the subgroups of GL(2), namely the maximally compact subgroups and the groups corresponding to simple Lie algebras? I understand that the topic is highly dependent on the field in question, but your insight and explanations are extremely valuable nonetheless.
2:58 why is k2 an extension of k1?
18:45 why the three notations for a field extension
The general statement here is that a domain has unique factorisation if and only if numbers can't indefinitely be subdivided under multiplication, and there exists a gcd-operation (up to units), with the following three properties: 1. If d|a, d|b, then d|(a,b) 2. (a,b) divides both a and b If there exist two of these operations, they divide each other, so they are equal (up to units). It also has some nice algebraic properties, such as (ad,bd)=(a,b)d. If p is prime, and p|ab, then (a,p)(b,p)=(ab,ap,bp,p²), and p divides the right side, so p divides the left side, so (a,p)(b,p)≠1, so p|a or p|b.
Can anyone please explain how he replaced A by the matrix with reA and imA ? And thank you
Beside all the interesting and insping maths, I love your humor, which is legendedry: My rabbits are spherical. Made my day :D:D:D Thank you
2(362310209.122785/(1008.185959)(.7071087516))^3 = 2(1008.185959(.7071087516)(508222.29668339))^2 where 1008.185959(.7071087516) = 362310209.122785/508222.29668339
(1.904631362/1.903613583) + (1.903613583/1.904631362) = 2.000000285
The comments at 7:40 really improved my personal experience with this.
Constructions using ruler and compass can also be made using only a compass.
Galois theory only describes the relation between fields up to their perfect closure, just as homological algebra only describes modules up to their injective envelope. So you might as well take Galois theory over perfect fields, since any other properties have to established seperately anyways. The advantage is that this gets rid of the concept of non-seperable extensions, so normal and Galois extensions are now the same thing, similar to the Galois correspondence in covering maps.
Idk how many videos Id been warching in a row but this is very entertaining and enlightning.....I was literally reading category theory a while ago and watched a video yesterday on the fundamental group so all this connections are so OP and beautiful
20:40 - You have also said before that Spec(k^n) has n points, but isn't that wrong? Take R^2. It has 3 prime ideals. The 0 ideal as well as the ones generated by (1,0) and (0,1), respectively. Those ideals are maximal as R^2/((1,0)) is isomorphic to R. In general, k^n should have Krull dimension n-1 and 2^n ideals, 2^n-1 of which prime, since the whole ring is not a prime ideal.
Great lectures! thank you. I didn't understand at 9:58, how is fact that abs(Z1*Z2)=abs(Z1)*abs(Z2) related to sqrt(x^2+y^2)=sqrt((x+iy)*(x-iy))
the best
-rep
You keep talking of "closures of points" and "closures of singletons" as in 22:30, but Spec(R) is always Tychonoff, or T1 space, so all singletons are closed sets.
The Zariski topology is not T1 in general. The non-closed points correspond to prime ideals which are not maximal.
@@boboryan1012 My bad. First of all, intead of Tychonoff I meant Frechet, or T1. I thought that Spec R is always T1. For some reason I had a false memory of reading that. Must have confused it with T0 or compactness or something, which it always satisfies.
If anyone knows: at 10:56, how do we know L even exists by only doing a countable number of iterations?
also the proof at 16:00 is really beautiful!
3:40 - Shouldn't Spec(k[x]/(x^2)) have two points? (0) and (x) := (x+(x^2))?
4:30 - and for that ring k[x]/(x^2-x), there is an isomorphism with k^2 given by x being sent to (1,0), 0 being sent to (0,0) and 1 being sent to (1,1). Then Spec(k^2) = {((0,0)), ((1,0)), ((0,1))}, so Spec(k[x]/(x^2-x)) should be {(0), (x), (1-x)}. Am I getting something wrong?
In both of your examples, 0 is not prime since both rings are not integral domains
@@boboryan1012 What? 0 is never a prime element of a ring by definition. The zero ideal (0)={0} is always a prime ideal in every ring, except itself, i.e. the trivial ring.
@@newwaveinfantry8362 0 is a prime ideal iff R is an integral domain...
@@boboryan1012 Completely forgot about that.
Did we just skip over why x is transcendental at 6:00 but spent an entire 3 minutes explaining the trivial case of cos 2pi/7? :D
at 1:27 Mr Borcherds says "...1 is a unit..." Can someone expand on this idea?
The best
Would have been a great talk, but the slides are out of focus. It was in focus for the first few seconds and then the focus suddenly changes and nothing can be read.
Borcherds concludes the proof of Hilbert 90 at about 15:17 by saying that θ + α•σ(θ) + α^2•σ^2(θ) + … = β. But this looks incorrect to me. The terms of β are (α•σ)^k(θ), which are not equal to (α^k)•σ^k(θ). E.g. (α•σ)^n = N(α)•σ^n = id ≠ (α^n)•σ^n unless α^n = 1. The proof still works, but we need to show that 1 + α•σ + (α•σ)^2 + … + (α•σ)^(n-1) is not identically = 0. It is a linear combination of the characters σ^k, but with coefficients 1, α, α•σ(α), etc.
The circle of the Fano plane shouldn't be outside the triangles, it is the line containing the three midpoints of the sides of the triangle.