2017
May
07

# Combinatorics: Jozsef Solymosi (UBC) Erdos lecture

11:00am to 1:00pm

2017
May
07

11:00am to 1:00pm

2017
Feb
09

12:00pm to 1:00pm

Manchester Building, Room 209

Title: The spectral method for geometric colouring problems

2017
Jun
29

12:00pm to 1:00pm

Manchester 209

Title: Stability patterns in representation theory and applications
Abstract:
Many natural sequences of objects come equipped with group actions, e.g. the symmetric group on n letters acting on a space X_n. This leads to fundamental instability of invariants, such as homology, arising from the representation theory of the sequence of groups. Representation stability is a new and increasingly important set of ideas that describe a sense in which such sequence of representations (of different groups) stabilizes.

2017
Jan
12

12:00pm to 1:00pm

Manchester Building, Room 209

Title: Semisimply degenerate quadratic forms and a conjecture of Grothendieck and Serre
(joint work with E. Bayer-Fluckiger)
Abstract:

2017
May
25

12:00pm to 1:00pm

Manchester 209

The existence of sharply 2-transitive groups without regular normal subgroup was a longstanding open problem. Recently constructions have been given, at least in certain characteristics. We will survey the current state of the art and explain some constructions and their limitations. (joint work with E. Rips)

2016
Dec
22

12:00pm to 1:00pm

Manchester Building, Room 209

Title: On groups with quadratic Dehn functions
Abstract: This is a joint work with A. Olshanskii. We construct a finitely presented group with quadratic Dehn function and undecidable conjugacy problem.

2017
Mar
23

12:00pm to 1:00pm

Manchester 209

Title: Pseudo-finite groups containing an involution with a finite centralizer.

2017
Jan
26

12:00pm to 1:00pm

Manchester Building, Room 209

Title: Approximations of groups and equations over groups.
Abstract:
The talk is largely based on the paper which may be found here:
https://authors.elsevier.com/a/1UN3b4~FOr6ze
Abstract: Let G be a group and K a class of groups. I define a notion of approximation of G by K and give several characterizations of approximable by K groups. For example, the sofic groups, defined by B. Weiss, are the groups approximable by symmetric (or alternating) groups. In the case of sofic groups we have that the following are equivalent:

2017
Jan
19

12:00pm to 1:00pm

Manchester Building, Room 209

Title: Old and New Results on Subgroup Growth in Pro-p Groups.
Abstract: I will survey our current knowledge about subgroup growth in pro-p growth. In particular I will present new solutions to long standing open problems in the area:
1. What is the minimal subgroup growth of non-$p$-adic analytic pro-$p$ groups? (Joint work with Benjamin Klopsch and Jan-Christoph Schlage-Puchta.)
2. What are the subgroup growths of the Grigorchuk group and the Gupta-Sidki groups? (Joint work with Jan-Christoph Schlage-Puchta.)

2017
Jun
22

12:00pm to 1:00pm

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

12:00pm to 1:00pm

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.

2017
May
04

12:00pm to 1:00pm

Manchester 209

Title: A tale of three elliptic curves.
Abstract: We will show how the arithmetic of three elliptic curves answers three old questions in the Euclidean geometry.

2016
Dec
08

12:00pm to 1:15pm

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

12:00pm to 1:00pm

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

2015
Dec
22

12:00pm to 1:00pm

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