2015
Dec
15

# Dynamics & probability: Omri Solan (TAU) - Divergent trajectories in SL_3(R)/SL_3(Z)

2:00pm to 4:30pm

## Location:

Manchester building, Hebrew University of Jerusalem, 209

Abstract:

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2015
Dec
15

2:00pm to 4:30pm

Manchester building, Hebrew University of Jerusalem, 209

Abstract:

2015
Nov
17

2:00pm to 3:00pm

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.

2015
Nov
24

2:00pm to 3:00pm

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
02

Repeats every week every Monday until Sun Nov 08 2015 .

11:00am to 1:00pmAbstract:
Expander graphs have many wonderful properties, and have been an immensely useful and fruitful area of research in both applicative and theoretical fields. There has been a lot of interest recently in the study of higher dimensional generalizations of expanders to d-uniform hypergraphs. Many competing definitions have been proposed, and different definitions may be appropriate depending on the property of expanders that we wish to preserve.

2015
Nov
17

12:00pm to 1:00pm

Manchester building, Hebrew University of Jerusalem, (Coffee Lounge)

Title: Invariant random subgroups

2015
Dec
29

12:00pm to 1:00pm

Manchester building, Hebrew University of Jerusalem, (Coffee lounge)

2015
Nov
03

12:00pm to 1:00pm

Manchester building, Hebrew University of Jerusalem, (Room 209)

Title: On the Mixing Property for Hyperbolic Systems [following a paper by Martine Babillot]

2016
Nov
01

Repeats every week every Tuesday until Tue Jan 24 2017 except Tue Nov 01 2016.

2:00pm to 3:00pm2:00pm to 3:00pm

2:00pm to 3:00pm

2:00pm to 3:00pm

2:00pm to 3:00pm

2:00pm to 3:00pm

2:00pm to 3:00pm

2:00pm to 3:00pm

2:00pm to 3:00pm

2:00pm to 3:00pm

2:00pm to 3:00pm

2:00pm to 3:00pm

2:00pm to 3:00pm

Manchester building, Hebrew University of Jerusalem, (Room 209)

Given a Z^d shift of finite type and a finite range shift-invariant interaction, we present sufficient conditions for efficient approximation of pressure and, in particular, topological entropy. Among these conditions, we introduce a combinatorial analog of the measure-theoretic property of Gibbs measures known as strong spatial mixing and we show that it implies many desirable properties in the context of symbolic dynamics. Next, we apply our

2017
Mar
16

4:00pm to 5:15pm

Ross 70

Title: What are amenable groups and why are groups non-amenable
Abstract: I will give an introduction to amenable
groups and explain the result of Kevin Whyte that a
countable non-amenable group admits a
"translation-like" action by a non-abelian free group.
I will also discuss (without proof) a measure theoretic
analogue of this result due to D. Gaboriau and R. Lyons.

2017
Mar
23

4:00pm to 5:15pm

Ross 70

Title: What are amenable groups and why are groups non-amenable
Abstract: I will give an introduction to amenable
groups and explain the result of Kevin Whyte that a
countable non-amenable group admits a
"translation-like" action by a non-abelian free group.
I will also discuss (without proof) a measure theoretic
analogue of this result due to D. Gaboriau and R. Lyons.

2017
Mar
09

4:00pm to 5:15pm

Ross 70

Title: What are amenable groups and why are groups non-amenable
Abstract: I will give an introduction to amenable
groups and explain the result of Kevin Whyte that a
countable non-amenable group admits a
"translation-like" action by a non-abelian free group.
I will also discuss (without proof) a measure theoretic
analogue of this result due to D. Gaboriau and R. Lyons.

2015
Dec
22

12:00pm to 1:00pm

Manchester building, Hebrew University of Jerusalem, (Coffee lounge)

2017
Jun
27

12:00pm to 1:00pm

Manchester building, Hebrew University of Jerusalem, (Coffee lounge)

2016
Nov
29

12:00pm to 1:00pm

Manchester building, Hebrew University of Jerusalem, (Coffee lounge)

I'll report on recent applications of the LLL to two problems in the dynamics of general countable groups. The first concerns the existence of free symbolic minimal actions; the second asks about realizations of URS's (uniformly recurrent subgroups) as stability systems.
I'll then concentrate on a solution of Gabor Elek to the second problem in the case of finitely generated groups.

2017
May
23

12:00pm to 1:00pm

Manchester building, Hebrew University of Jerusalem, (Coffee lounge)