Ical
https://mathematics.huji.ac.il/calendar?type=month&month=term
en<a href="https://mathematics.huji.ac.il/event/special-analysis-seminar-sergey-denissov-wisconsin?delta=0" >Special Analysis Seminar: Sergey Denisov (Wisconsin) "Szego theorem for measures on the real line: optimal results and applications"</a>
https://mathematics.huji.ac.il/event/special-analysis-seminar-sergey-denissov-wisconsin
Title: Szego theorem for measures on the real line: optimal results and
applications.
Abstract: Measures on the unit circle for which the logarithmic integral
converges can be characterized in many different ways: e.g., through
their Schur parameters or through the predictability of the future from
the past in Gaussian stationary stochastic process. In this talk, we
consider measures on the real line for which logarithmic integral exists
and give their complete characterization in terms of the Hamiltonian in
De Branges canonical system. This provides a generalization of the
classical Szego theorem for polynomials orthogonal on the unit circle
and complements the celebrated Krein-Wiener theorem in complex function
theory. The applications to Krein strings and Gaussian processes with
continuous time will be discussed (this talk is based on the joint paper
with R. Bessonov).Sun, 18 Nov 2018 10:00:00 +0000Anonymous64919 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/kazhdan-seminar-tomer-schlank-nonabelian-chabauty-method-4?delta=0" >Kazhdan seminar: Tomer Schlank "The Nonabelian Chabauty Method" </a>
https://mathematics.huji.ac.il/event/kazhdan-seminar-tomer-schlank-nonabelian-chabauty-method-4
Abstract:
The Chabauty method is a remarkable tool which employs p-adic analitic methods (in particular Colman integration.) To study rational points on curves. However the method can be applied only when the genus of the curve in question is larger than its Mordell-Weil rank. Kim developed a sophisticated "nonableian" generalisation.
We shall present the classical methid, and give an approachable introduction to Kim's method.
I'm basically going to follow <a href="http://math.mit.edu/nt/old/stage_s18.html">http://math.mit.edu/nt/old/stage_s18.html</a>Sun, 18 Nov 2018 10:00:00 +0000Anonymous66572 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/kazhdan-seminar-karim-adiprasito-positivity-combinatorics-and-beyond-5?delta=0" >Kazhdan seminar: Karim Adiprasito "Positivity in combinatorics and beyond" </a>
https://mathematics.huji.ac.il/event/kazhdan-seminar-karim-adiprasito-positivity-combinatorics-and-beyond-5
Abstract: I will discuss applications of algebraic results to combinatorics, focusing in particular on Lefschetz theorem, Decomposition theorem and Hodge Riemann relations. Secondly, I will discuss proving these results combinatorially, using a technique by McMullen and extended by de Cataldo and Migliorini. Finally, I will discuss Lefschetz type theorems beyond positivity.
Recommended prerequisites: basic commutative algebraSun, 18 Nov 2018 13:00:00 +0000Anonymous66586 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/combinatorics-michael-simkin-hu-tba?delta=0" >Combinatorics: Michael Simkin, HU, "The threshold problem for Latin squares"</a>
https://mathematics.huji.ac.il/event/combinatorics-michael-simkin-hu-tba
Speaker: Michael Simkin, HU
Title: The threshold problem for Latin squares
Abstract: An order-$n$ Latin square is equivalent to a triangle-decomposition of the complete tripartite graph $K_{n,n,n}$. Let $H \sim H_3(n,n,n;p)$ be a tripartite, balanced, binomial random $3$-uniform hypergraph on $3n$ vertices where each edge is present with probability $p$. What is the threshold $p$ for the property that $H$ contains an order-$n$ Latin square? The general heuristic is that spanning structures appear together with the disappearance of local obstructions. Thus the natural conjecture is $p = 2 \log(n) / n$, which corresponds to the disappearance of edges not contained in any triangle.
While this problem remains open, two natural approaches are to consider approximations of Latin squares, and to obtain (possibly suboptimal) upper bounds on the threshold probability. I will review results in both directions.
The lion's share of the talk will be spent discussing an application of Keevash's method of randomized algebraic construction to show an upper bound of $n^{-1/7+ o(1)}$ on the threshold probability.
Parts of the talk are the result of joint work with Zur Luria.Mon, 19 Nov 2018 09:00:00 +0000Anonymous66143 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/nt-ag-lunch-sazzad-biswas-local-gamma-factors-and-converse-problems?delta=0" >NT & AG Lunch: Sazzad Biswas "Local gamma factors, and converse problems" </a>
https://mathematics.huji.ac.il/event/nt-ag-lunch-sazzad-biswas-local-gamma-factors-and-converse-problems
Let F be a non-Archimedean local field. In the representation theory of GL_n(F), one of the basic problems is to characterize its irreducible representations up to isomorphism. There are many invariants (e.g., epsilon factors, L-functions, gamma factors, depth, etc) that we can attach to a representation of GL_n(F). Roughly, the local converse problem is to find the smallest subcollection of twisted local \gamma-factors which classifies the
irreducible admissible representations of GL_n(F) up to isomorphism.
Since the local gamma-factor is the main ingredient of the converse problem, first, we will try to understand the local gamma-factors and their properties.
Then we will discuss the local converse theorems and related problems.
Key words: Local fields, Reductive groups, Generic representation, Whittaker model, L- and \epsilon-factors, local gamma factor, Local converse theoremMon, 19 Nov 2018 11:00:00 +0000Anonymous68032 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/ntag-gaku-liu-max-planck-institute-mathematics-semistable-reduction-characteristic-0?delta=0" >NT&AG: Gaku Liu (Max Planck Institute of Mathematics), "Semistable reduction in characteristic 0"</a>
https://mathematics.huji.ac.il/event/ntag-gaku-liu-max-planck-institute-mathematics-semistable-reduction-characteristic-0
We address the semistable reduction conjecture of Abramovich and Karu: we prove that every surjective morphism of complex projective varieties can be modified to a semistable one. The key ingredient is a combinatorial result on triangulating lattice Cayley polytopes. Joint work with Karim Adiprasito and Michael Temkin.
The lecture consists of two parts: first 30 minutes an algebra-geometric introduction by Michael Temkin, and then a one hour talk by Gaku Liu about the key combinatorial result.Mon, 19 Nov 2018 12:30:00 +0000Anonymous68236 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/dynamics-lunch-jiange-li-sumsets-and-entropy-after-ruzsa?delta=0" >Dynamics Lunch: Jiange Li "Sumsets and entropy" after Ruzsa</a>
https://mathematics.huji.ac.il/event/dynamics-lunch-jiange-li-sumsets-and-entropy-after-ruzsa
Tue, 20 Nov 2018 10:00:00 +0000Anonymous68186 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/tg-gangotryi-sorcar-hebrew-university-topology-teichmuller-space-negatively-curved?delta=0" >T&G: Gangotryi Sorcar (Hebrew University), On the topology of the Teichmuller space of negatively curved Riemannian metrics</a>
https://mathematics.huji.ac.il/event/tg-gangotryi-sorcar-hebrew-university-topology-teichmuller-space-negatively-curved
This talk is a survey on results concerning the Teichmuller space of negatively curved Riemannian metrics on M. It is defined as the quotient space of the space of all negatively curved Riemannian metrics on M modulo the space of all isotopies of M that are homotopic to the identity. This space was shown to have highly non-trivial homotopy when M is real hyperbolic by Tom Farrell and Pedro Ontaneda in 2009. Then in 2015, it was shown to be non simply connected in my thesis when M is a suitably chosen Gromov-Thurston manifold (which are examples of negatively curved non-locally symmetric spaces). In 2017, Tom Farrell and myself proved a similar result for M being a suitable complex hyperbolic manifold. In all these results, the dimension of M has to be 4k − 2 for some k greater or equal to 2. In this talk, I will explain this project, and talk about the tools we have used so far in unraveling it. I will also mention the cases that are still open in this project.Tue, 20 Nov 2018 12:00:00 +0000Anonymous68286 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/yan-dolinsky-huji-and-monash?delta=0" >Dynamics Seminar: Yuri Kifer, Geometric law of multiple returns until a hazard</a>
https://mathematics.huji.ac.il/event/yan-dolinsky-huji-and-monash
Tue, 20 Nov 2018 12:15:00 +0000matans64469 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/analysis-seminar-asaf-shachar-tba?delta=0" >Analysis Seminar: Asaf Shachar (HUJI) "Regularity via minors and applications to conformal maps"</a>
https://mathematics.huji.ac.il/event/analysis-seminar-asaf-shachar-tba
Title:
Regularity via minors and applications to conformal maps.
Abstract:
Let f:\mathbb{R}^n \to \mathbb{R}^n be a Sobolev map; Suppose that the k-minors of df are smooth. What can we say about the regularity of f?
This question arises naturally in the context of Liouville's theorem, which states that every weakly conformal map is smooth. I will explain the connection of the minors question to the conformal regularity problem, and describe a regularity result for maps with regular minors.
If time permits, I will discuss these questions in the context of mappings between Riemannian manifolds.Wed, 21 Nov 2018 10:00:00 +0000Anonymous64116 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/set-theory-seminar-yair-hayut-changs-conjecture?delta=0" >Set Theory Seminar: Yair Hayut "Chang's Conjecture"</a>
https://mathematics.huji.ac.il/event/set-theory-seminar-yair-hayut-changs-conjecture
Title: Chang's Conjecture (joint with Monroe Eskew)
Abstract:
I will review some consistency results related to Chang's Conjecture (CC).
First I will discuss some classical results of deriving instances of CC from huge cardinals and the new results for getting instances of CC from supercompact cardinals, and present some open problems.
Then, I will review the consistency proof of some versions of the Global Chang's Conjecture - which is the consistency of the occurrence many instances of CC simultaneously.
We will aim to show the consistency of the statement: (\mu^+,\mu) -->> (
u^+,
u) for all regular \mu and all
u < \mu, starting from a huge cardinal. In order to prove this we will start with the easier task in which $\mu$ is assumed to be regular. In order to get the stronger result, we will force with Radin forcing over a model in which many instances of CC hold.Wed, 21 Nov 2018 12:00:00 +0000Anonymous68280 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/%D7%A2%D7%9E%D7%99%D7%97%D7%99-%D7%9C%D7%9E%D7%A4%D7%A8%D7%98-%D7%A7%D7%91%D7%95%D7%A6%D7%95%D7%AA-%D7%90%D7%97%D7%99%D7%93%D7%95%D7%AA-%D7%A4%D7%95%D7%A8%D7%99%D7%99%D7%94?delta=0" >Graduate Student Seminar: Amichai Lampert - Fourier Uniform Sets</a>
https://mathematics.huji.ac.il/event/%D7%A2%D7%9E%D7%99%D7%97%D7%99-%D7%9C%D7%9E%D7%A4%D7%A8%D7%98-%D7%A7%D7%91%D7%95%D7%A6%D7%95%D7%AA-%D7%90%D7%97%D7%99%D7%93%D7%95%D7%AA-%D7%A4%D7%95%D7%A8%D7%99%D7%99%D7%94
Abstract: Let G be a finite abelian group. We say that a given subset of G is uniform if all of its Fourier coefficients are small. We'll show that uniform sets are common and explore some of their nice additive properties.Wed, 21 Nov 2018 14:00:00 +0000Anonymous67687 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/colloquium-5?delta=0" >Colloquium: Spencer Unger (HUJI) - A constructive solution to Tarski's circle squaring problem</a>
https://mathematics.huji.ac.il/event/colloquium-5
In 1925, Tarski asked whether a disk in R^2 can be partitioned into finitely many pieces which can be rearranged by isometries to form a square of the same area. The restriction of having a disk and a square with the same area is necessary. In 1990, Laczkovich gave a positive answer to the problem using the axiom of choice. We give a completely explicit (Borel) way to break the circle and the square into congruent pieces. This answers a question of Wagon. Our proof has three main components. The first is work of Laczkovich in Diophantine approximation. The second is recent progress in a program of descriptive set theory to understand the complexity of actions of amenable groups. The third is the study of flows in networks. This is joint work with Andrew Marks.Thu, 22 Nov 2018 12:30:00 +0000Anonymous63634 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/basic-notions-seminar-zlil-sela-basic-conjectures-and-preliminary-results-non-0?delta=0" >Basic Notions seminar : Zlil Sela - Basic conjectures and preliminary results in non-commutative algebraic geometry</a>
https://mathematics.huji.ac.il/event/basic-notions-seminar-zlil-sela-basic-conjectures-and-preliminary-results-non-0
<b>Speaker: Zlil Sela</b><br /><b>Title: Basic conjectures and preliminary results in non-commutative algebraic geometry</b><br /><b></b><br /> <b>Abstract</b>: Algebraic geometry studies the structure of varieties over<br /> fields and commutative rings. Starting in the 1960's ring theorists<br /> (Cohn, Bergman and others) have tried to study the structure of varieties<br /> over some non-commutative rings (notably free associative algebras).<br /><br /> The lack of unique factorization that they tackled and studied in detail,<br /> and the pathologies that they were aware of, prevented any attempt<br /> to prove or even speculate what can be the properties of such varieties.<br /><br /> Using techniques and concepts from geometric group theory and from low<br /> dimensional topology, we formulate concrete conjectures about the<br /> structure of these varieties, and prove preliminary results in the<br /> direction of these conjectures. Further (possible) applications to the<br /> study of representations into free associative algebras will also be<br /> discussed.<br /><br /> We intend to survey the relevant background from geometric group theory,<br /> and some from low dimensional topology, including the structure of<br /> varieties over free groups and semigroups that motivate the conjectures.Thu, 22 Nov 2018 14:00:00 +0000Anonymous67796 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/kazhdan-seminar-tomer-schlank-nonabelian-chabauty-method-5?delta=0" >Kazhdan seminar: Tomer Schlank "The Nonabelian Chabauty Method" </a>
https://mathematics.huji.ac.il/event/kazhdan-seminar-tomer-schlank-nonabelian-chabauty-method-5
Abstract:
The Chabauty method is a remarkable tool which employs p-adic analitic methods (in particular Colman integration.) To study rational points on curves. However the method can be applied only when the genus of the curve in question is larger than its Mordell-Weil rank. Kim developed a sophisticated "nonableian" generalisation.
We shall present the classical methid, and give an approachable introduction to Kim's method.
I'm basically going to follow <a href="http://math.mit.edu/nt/old/stage_s18.html">http://math.mit.edu/nt/old/stage_s18.html</a>Sun, 25 Nov 2018 10:00:00 +0000Anonymous66573 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/kazhdan-seminar-karim-adiprasito-positivity-combinatorics-and-beyond-6?delta=0" >Kazhdan seminar: Karim Adiprasito "Positivity in combinatorics and beyond" </a>
https://mathematics.huji.ac.il/event/kazhdan-seminar-karim-adiprasito-positivity-combinatorics-and-beyond-6
Abstract: I will discuss applications of algebraic results to combinatorics, focusing in particular on Lefschetz theorem, Decomposition theorem and Hodge Riemann relations. Secondly, I will discuss proving these results combinatorially, using a technique by McMullen and extended by de Cataldo and Migliorini. Finally, I will discuss Lefschetz type theorems beyond positivity.
Recommended prerequisites: basic commutative algebraSun, 25 Nov 2018 13:00:00 +0000Anonymous66587 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/nt-ag-lunch-tba-9?delta=0" >NT & AG Lunch: TBA</a>
https://mathematics.huji.ac.il/event/nt-ag-lunch-tba-9
Mon, 26 Nov 2018 11:00:00 +0000Anonymous68030 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/dynamics-lunch-jakub-konieczny?delta=0" >Dynamics Lunch: Tom Gilat</a>
https://mathematics.huji.ac.il/event/dynamics-lunch-jakub-konieczny
Tue, 27 Nov 2018 10:00:00 +0000Anonymous64264 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/amir-dembo-stanford-large-deviations-subgraph-counts-sparse-random-graphs?delta=0" >Amir Dembo (Stanford), Large deviations of subgraph counts for sparse random graphs</a>
https://mathematics.huji.ac.il/event/amir-dembo-stanford-large-deviations-subgraph-counts-sparse-random-graphs
For fixed t>1 and L>3 we establish sharp asymptotic formula for
the log-probability that the number of cycles of length L in the Erdos - Renyi
random graph G(N,p) exceeds its expectation by a factor t, assuming only that
p >> log N/sqrt(N). In a narrower range of p=p(N) we obtain such sharp upper tail
for general subgraph counts and for the Schatten norms of the corresponding adjacency
matrices.
In this talk, based on a joint work with Nick Cook, I will explain our approach,
based on convex-covering and a new quantitative refinement of
Szemeredi's regularity lemma for sparse random graphs in the large deviations regime.Tue, 27 Nov 2018 12:15:00 +0000Anonymous67602 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/jerusalem-analysis-seminar-netanel-levi?delta=0" >Analysis Seminar: Netanel Levi </a>
https://mathematics.huji.ac.il/event/jerusalem-analysis-seminar-netanel-levi
Wed, 28 Nov 2018 10:00:00 +0000Anonymous64122 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/colloquium-chaya-keller-bgu?delta=0" >Colloquium: Chaya Keller (BGU)</a>
https://mathematics.huji.ac.il/event/colloquium-chaya-keller-bgu
Thu, 29 Nov 2018 12:30:00 +0000Anonymous63638 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/kazhdan-seminar-tomer-schlank-nonabelian-chabauty-method-6?delta=0" >Kazhdan seminar: Tomer Schlank "The Nonabelian Chabauty Method" </a>
https://mathematics.huji.ac.il/event/kazhdan-seminar-tomer-schlank-nonabelian-chabauty-method-6
Abstract:
The Chabauty method is a remarkable tool which employs p-adic analitic methods (in particular Colman integration.) To study rational points on curves. However the method can be applied only when the genus of the curve in question is larger than its Mordell-Weil rank. Kim developed a sophisticated "nonableian" generalisation.
We shall present the classical methid, and give an approachable introduction to Kim's method.
I'm basically going to follow <a href="http://math.mit.edu/nt/old/stage_s18.html">http://math.mit.edu/nt/old/stage_s18.html</a>Sun, 02 Dec 2018 10:00:00 +0000Anonymous66574 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/kazhdan-seminar-karim-adiprasito-positivity-combinatorics-and-beyond-7?delta=0" >Kazhdan seminar: Karim Adiprasito "Positivity in combinatorics and beyond" </a>
https://mathematics.huji.ac.il/event/kazhdan-seminar-karim-adiprasito-positivity-combinatorics-and-beyond-7
Abstract: I will discuss applications of algebraic results to combinatorics, focusing in particular on Lefschetz theorem, Decomposition theorem and Hodge Riemann relations. Secondly, I will discuss proving these results combinatorially, using a technique by McMullen and extended by de Cataldo and Migliorini. Finally, I will discuss Lefschetz type theorems beyond positivity.
Recommended prerequisites: basic commutative algebraSun, 02 Dec 2018 13:00:00 +0000Anonymous66588 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/nt-ag-lunch-tba-8?delta=0" >NT & AG Lunch: TBA</a>
https://mathematics.huji.ac.il/event/nt-ag-lunch-tba-8
Mon, 03 Dec 2018 11:00:00 +0000Anonymous68029 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/dynamics-lunch-manuel-luethi?delta=0" >Dynamics Lunch: Manuel Luethi</a>
https://mathematics.huji.ac.il/event/dynamics-lunch-manuel-luethi
Tue, 04 Dec 2018 10:00:00 +0000Anonymous64576 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/omri-sarig-weizmann?delta=0" >Dynamics Seminar: Omri Sarig (Weizmann)</a>
https://mathematics.huji.ac.il/event/omri-sarig-weizmann
Tue, 04 Dec 2018 12:15:00 +0000Anonymous64470 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/logic-seminar-omer-ben-neria?delta=0" >Logic Seminar - Omer Ben-Neria</a>
https://mathematics.huji.ac.il/event/logic-seminar-omer-ben-neria
<b>tba<br /></b><b></b><b><br /></b>Wed, 05 Dec 2018 09:00:00 +0000Anonymous68080 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/huji-analysis-seminar-ron-rosenthal-technion?delta=0" >Analysis Seminar: Ron Rosenthal (Technion)</a>
https://mathematics.huji.ac.il/event/huji-analysis-seminar-ron-rosenthal-technion
Wed, 05 Dec 2018 10:00:00 +0000Anonymous64266 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/%D7%93%D7%A0%D7%99%D7%90%D7%9C-%D7%90%D7%95%D7%A4%D7%A0%D7%A8-%D7%9E%D7%98%D7%A8%D7%99%D7%A6%D7%95%D7%AA-%D7%90%D7%A7%D7%A8%D7%90%D7%99%D7%95%D7%AA?delta=0" >דניאל אופנר - מטריצות אקראיות</a>
https://mathematics.huji.ac.il/event/%D7%93%D7%A0%D7%99%D7%90%D7%9C-%D7%90%D7%95%D7%A4%D7%A0%D7%A8-%D7%9E%D7%98%D7%A8%D7%99%D7%A6%D7%95%D7%AA-%D7%90%D7%A7%D7%A8%D7%90%D7%99%D7%95%D7%AA
Wed, 05 Dec 2018 14:00:00 +0000matans67686 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/colloquium-naomi-feldheim-weizman?delta=0" >Colloquium: Naomi Feldheim (Weizman)</a>
https://mathematics.huji.ac.il/event/colloquium-naomi-feldheim-weizman
Thu, 06 Dec 2018 12:30:00 +0000Anonymous63714 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/tomer-schlank-nonabelian-chabauty-method?delta=0" >Kazhdan seminar: Tomer Schlank "The Nonabelian Chabauty Method" </a>
https://mathematics.huji.ac.il/event/tomer-schlank-nonabelian-chabauty-method
Abstract:
The Chabauty method is a remarkable tool which employs p-adic analitic methods (in particular Colman integration.) To study rational points on curves. However the method can be applied only when the genus of the curve in question is larger than its Mordell-Weil rank. Kim developed a sophisticated "nonableian" generalisation.
We shall present the classical methid, and give an approachable introduction to Kim's method.
I'm basically going to follow <a href="http://math.mit.edu/nt/old/stage_s18.html">http://math.mit.edu/nt/old/stage_s18.html</a>Sun, 09 Dec 2018 10:00:00 +0000Anonymous65204 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/kazhdan-seminar-karim-adiprasito-positivity-combinatorics-and-beyond-8?delta=0" >Kazhdan seminar: Karim Adiprasito "Positivity in combinatorics and beyond" </a>
https://mathematics.huji.ac.il/event/kazhdan-seminar-karim-adiprasito-positivity-combinatorics-and-beyond-8
Abstract: I will discuss applications of algebraic results to combinatorics, focusing in particular on Lefschetz theorem, Decomposition theorem and Hodge Riemann relations. Secondly, I will discuss proving these results combinatorially, using a technique by McMullen and extended by de Cataldo and Migliorini. Finally, I will discuss Lefschetz type theorems beyond positivity.
Recommended prerequisites: basic commutative algebraSun, 09 Dec 2018 13:00:00 +0000Anonymous66589 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/erdos-lecture-igor-pak-ucla-tba?delta=0" >Erdos lecture I: Igor Pak, UCLA, "Counting linear extensions and Young tableaux"</a>
https://mathematics.huji.ac.il/event/erdos-lecture-igor-pak-ucla-tba
Speaker: Igor Pak, UCLA
Title: Counting linear extensions.
Abstract:
I will survey various known and recent results on counting the number of linear extensions of finite posets. I will emphasize the asymptotic and complexity aspects for special families, where the problem is especially elegant yet remains #P-complete. In the second half of the talk I will turn to posets corresponding to (skew) Young diagrams. This special case is important for many applications in representation theory and algebraic geometry. I will explain some surprising product formulas, connections to lozenge tilings, Selberg integrals and certain particle systems.Mon, 10 Dec 2018 09:00:00 +0000Anonymous64649 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/nt-ag-lunch-tba-7?delta=0" >NT & AG Lunch: TBA</a>
https://mathematics.huji.ac.il/event/nt-ag-lunch-tba-7
Mon, 10 Dec 2018 11:00:00 +0000Anonymous68028 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/demi-allen-manchester?delta=0" >Demi Allen (Manchester)</a>
https://mathematics.huji.ac.il/event/demi-allen-manchester
Tue, 11 Dec 2018 12:15:00 +0000Anonymous67601 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/cs-theory-erd%C5%91s-lecture-igor-pak-ucla-counting-young-tableaux?delta=0" >CS Theory -- Erdős Lecture: Igor Pak (UCLA) : Counting Young tableaux</a>
https://mathematics.huji.ac.il/event/cs-theory-erd%C5%91s-lecture-igor-pak-ucla-counting-young-tableaux
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The number of standard Young tableaux of skew shape is a mesmerizing special case of the number of linear extensions of posets, that is important for applications in representation theory and algebraic geometry. In this case there is a determinant formula, but finding their asymptotics is a difficult challenge. I will survey some of the many beautiful result on the subject, explain some surprising product formulas, connections to Selberg integral, lozenge tilings and certain particle systems.
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This talk is independent of the first Erdős Lecture.
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Wed, 12 Dec 2018 08:30:00 +0000naavahl58788 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/logic-seminar-ilijas-farah?delta=0" >Logic Seminar - Ilijas Farah</a>
https://mathematics.huji.ac.il/event/logic-seminar-ilijas-farah
<b>tba<br /></b><b></b><b><br /></b>Wed, 12 Dec 2018 09:00:00 +0000Anonymous67925 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/jerusalem-analysis-seminar-barry-simon-poneclet%E2%80%99s-theorem-paraorthogonal-polynomials?delta=0" >Analysis Seminar: Barry Simon "Poneclet’s Theorem, Paraorthogonal Polynomials and the Numerical Range of Truncated GGT matrices"</a>
https://mathematics.huji.ac.il/event/jerusalem-analysis-seminar-barry-simon-poneclet%E2%80%99s-theorem-paraorthogonal-polynomials
Abstract: During the last 20 years there has been a considerable literature on a collection of related mathematical topics: higher degree versions of Poncelet’s Theorem, certain measures associated to some finite Blaschke products and the numerical range of finite dimensional completely non-unitary contractions with defect index 1. I will explain that without realizing it, the authors of these works were discussing OPUC. This will allow us to use OPUC methods to provide illuminating proofs of some of their results and in turn to allow the insights from this literature to tell us something about OPUC. In particular, I’ll discuss a Wendroff theorem for POPUC. This is joint work with Andrei Martínez-Finkelshtein and Brian Simanek.Wed, 12 Dec 2018 10:00:00 +0000Anonymous64123 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/colloquium-erdos-lecture-igor-pak-ucla?delta=0" >Erdős Lecture 2: Igor Pak (UCLA), TBA</a>
https://mathematics.huji.ac.il/event/colloquium-erdos-lecture-igor-pak-ucla
Thu, 13 Dec 2018 12:30:00 +0000Anonymous63636 at https://mathematics.huji.ac.il<a href="https://mathematics.huji.ac.il/event/kazhdan-seminar-tomer-schlank-nonabelian-chabauty-method-7?delta=0" >Kazhdan seminar: Tomer Schlank "The Nonabelian Chabauty Method" </a>
https://mathematics.huji.ac.il/event/kazhdan-seminar-tomer-schlank-nonabelian-chabauty-method-7
Abstract:
The Chabauty method is a remarkable tool which employs p-adic analitic methods (in particular Colman integration.) To study rational points on curves. However the method can be applied only when the genus of the curve in question is larger than its Mordell-Weil rank. Kim developed a sophisticated "nonableian" generalisation.
We shall present the classical methid, and give an approachable introduction to Kim's method.
I'm basically going to follow <a href="http://math.mit.edu/nt/old/stage_s18.html">http://math.mit.edu/nt/old/stage_s18.html</a>Sun, 16 Dec 2018 10:00:00 +0000Anonymous66575 at https://mathematics.huji.ac.il