Events & Seminars

2017 Jun 22

Amitsur Algebra: Jan Dobrowolski

12:00pm to 1:00pm

Location: 

Manchester 209
Title: Inp-minimal ordered groups.
Abstract. The main goal of the talk is to present the proof of the theorem stating that inp-minimal (left)-ordered groups are abelian. This generalizes a previous result of P. Simon for bi-ordered inp-minimal groups.
2016 Dec 29

Amitsur Algebra: Igor Rivin, "Random integer matrices"

12:00pm to 1:00pm

Location: 

Manchester Building, Room 209
Title: Random integer matrices
Abstract: I will discuss various models of random integer matrices, and their (occasionally surprising) properties. Some of the work discussed is joint with E. Fuchs.
2016 Dec 08

Amitsur Algebra: George Glauberman (Chicago)

12:00pm to 1:15pm

Location: 

Manchester Building, Room 209
Title: Fixed points of finite groups on modules
Abstract: Suppose G is a finite group, p is a prime, S is a Sylow p-subgroup of G, and V is a G-module over a field of characteristic p. In some situations, an easy calculation shows that the fixed points of G on V are the same as the fixed points of the normalizer
of S in G. Generalizations of this result have been obtained previously to study the structure of G for p odd. We plan to describe a new generalization for p = 2. (This is part of joint work with J. Lynd that removes the classification of finite simple groups
2017 Mar 02

Amitsur Algebra: Lev Glebsky, " Almost Congruence Extension Property for subgroups of free groups"

12:00pm to 1:00pm

Location: 

Manchester Building, Room 209
Title: Almost Congruence Extension Property for subgroups of free groups.
Abstract.
The talk essentially based on: https://arxiv.org/abs/1606.02345
Let G be a group and H every normal subgroup N of H is an intersection of some normal subgroup of G with H. The CEP appears in group theory in different context.
The following question seems to be very difficult:
Which finitely generated subgroup of a free group has CEP?
2015 Nov 19

Groups & dynamics: Lei Yang (HUJI) "Equidistribution of expanding translates of curves in homogeneous spaces and Diophantine approximation"

10:00am to 11:00am

Location: 

Ross 70
Title: Equidistribution of expanding translates of curves in homogeneous spaces and Diophantine approximation. Abstract: We consider an analytic curve $\varphi: I \rightarrow \mathbb{M}(n\times m, \mathbb{R}) \hookrightarrow \mathrm{SL}(n+m, \mathbb{R})$ and embed it into some homogeneous space $G/\Gamma$, and translate it via some diagonal flow
2015 Nov 24

Dynamics & probability: Yaar Salomon (Stonybrook) "The Danzer problem and a solution to a related problem of Gowers"

2:00pm to 3:00pm

Location: 

Manchester building, Hebrew University of Jerusalem, (Room 209)
The Danzer problem and a solution to a related problem of Gowers Is there a point set Y in R^d, and C>0, such that every convex set of volume 1 contains at least one point of Y and at most C? This discrete geometry problem was posed by Gowers in 2000, and it is a special case of an open problem posed by Danzer in 1965. I will present two proofs that answers Gowers' question with a NO. The first approach is dynamical; we introduce a dynamical system and classify its minimal subsystems. This classification in particular yields the negative answer to Gowers'
2015 Nov 03

Dynamics lunch: Or Landesberg (HUJI)

12:00pm to 1:00pm

Location: 

Manchester building, Hebrew University of Jerusalem, (Room 209)
Title: On the Mixing Property for Hyperbolic Systems [following a paper by Martine Babillot]
2015 Dec 02

Dynamics & probability: Ron Rosenthal (ETHZ) "Local limit theorem for certain ballistic random walks in random environments"

2:00pm to 3:00pm

Location: 

Ross 70
Title: Local limit theorem for certain ballistic random walks in random environments Abstract: We study the model of random walks in random environments in dimension four and higher under Sznitman's ballisticity condition (T'). We prove a version of a local Central Limit Theorem for the model and also the existence of an equivalent measure which is invariant with respect to the point of view of the particle. This is a joint work with Noam Berger and Moran Cohen.
2015 Nov 17

Dynamics & probability: Sebastian Donoso (HUJI), "Topological structures and the pointwise convergence of some averages for commuting transformations"

2:00pm to 3:00pm

Location: 

Manchester building, Hebrew University of Jerusalem, (Room 209)
Title: Topological structures and the pointwise convergence of some averages for commuting transformations Abstract: ``Topological structures'' associated to a topological dynamical system are recently developed tools in topological dynamics. They have several applications, including the characterization of topological dynamical systems, computing automorphisms groups and even the pointwise convergence of some averages.  In this talk I will discuss some developments of this subject, emphasizing applications to the pointwise convergence of some averages.

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