Events & Seminars

2019 Jun 03

NT & AG Seminar: Shuddhodan K V (HUJI) "Self maps of varieties over finite fields"

2:30pm to 3:30pm

Location: 

Ross building 70
Title: Title: Self maps of varieties over finite fields
Abstract: Esnault and Srinivas proved that as in Betti cohomology over the complex numbers, the value of the entropy of an automorphism of a smooth proper surface over a finite field $\F_q$ is taken in the subspace spanned by algebraic cycles inside $\ell$-adic cohomology. In this talk we will discuss some analogous questions in higher dimensions motivated by their results and techniques.
2019 May 21

Special groups theory seminar: Abdalrazzaq R A Zalloum (Suny Buffalo) "Regular languages for hyperbolic-like geodesics".

4:00pm to 5:00pm

Location: 

Ross 63
Combinatorial group theory began with Dehn's study of surface
groups, where he used arguments from hyperbolic geometry to solve the
word/conjugacy problems. In 1984, Cannon generalized those ideas to all
"hyperbolic groups", where he was able to give a solution to the
word/conjugacy problem, and to show that their growth function satisfies
a finite linear recursion. The key observation that led to his
discoveries is that the global geometry of a hyperbolic group is determined locally:
2019 May 21

Special groups theory seminar: Abdalrazzaq R A Zalloum (Suny Buffalo) "Regular languages for hyperbolic-like geodesics".

4:00pm to 5:00pm

Location: 

Ross 63
Combinatorial group theory began with Dehn's study of surface groups, where he used arguments from hyperbolic geometry to solve the word/conjugacy problems. In 1984, Cannon generalized those ideas to all "hyperbolic groups", where he was able to give a solution to the word/conjugacy problem, and to show that their growth function satisfies a finite linear recursion. The key observation that led to his discoveries is that the global geometry of a hyperbolic group is determined locally: first, one discovers the local picture of G, then the recursive structure
2019 Jun 04

Dynamics Seminar: Arie Levit - Surface groups are flexibly stable

12:00pm to 1:00pm

This will be a research talk. The abstract is below:
A group G is stable in permutations if every almost-action of G on a finite set is close to some actual action. Part of the interest in this notion comes from the observation that a non-residually finite stable group cannot be sofic. 
I will show that surface groups are stable in a flexible sense, that is if one is allowed to "add a few extra points" to the action. This is the first non-trivial stability result for a non-amenable group. 
2019 May 13

NT & AG Seminar: "A dream desingularization algorithm", Michael Temkin (HU)

2:30pm to 4:00pm

Location: 

Ross 70
Abstract: Any birational geometer would agree that the best algorithm
for resolution of singularities should run by defining a simple invariant of
the singularity and iteratively blowing up its maximality locus.
The only problem is that already the famous example of Whitney umbrella
shows that this is impossible, and all methods following Hironaka had
to use some history and resulted in more complicated algorithms.
Nevertheless, in a recent work with Abramovich and Wlodarczyk we did

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