Seminar Calendar
for Group Theory Seminar events the next 12 months of Saturday, August 1, 2009.

     .
events for the
events containing  

(Requires a password.)
More information on this calendar program is available.
Questions regarding events or the calendar should be directed to Tori Corkery. 
      July 2009             August 2009           September 2009   
 Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa
           1  2  3  4                      1          1  2  3  4  5
  5  6  7  8  9 10 11    2  3  4  5  6  7  8    6  7  8  9 10 11 12
 12 13 14 15 16 17 18    9 10 11 12 13 14 15   13 14 15 16 17 18 19
 19 20 21 22 23 24 25   16 17 18 19 20 21 22   20 21 22 23 24 25 26
 26 27 28 29 30 31      23 24 25 26 27 28 29   27 28 29 30         
                        30 31

Thursday, August 27, 2009

Group Theory Seminar
1:00 pm   in Altgeld Hall 347,  Thursday, August 27, 2009
 Del 
 Edit 
 Copy 
Submitted by kapovitc.
Organizational meeting

Thursday, September 10, 2009

Group Theory Seminar
1:00 pm   in 347 Altgeld Hall,  Thursday, September 10, 2009
 Del 
 Edit 
 Copy 
Submitted by ivanov.
Sergei Ivanov (UIUC Math)
A property of groups and the Kurosh rank of the intersection of subgroups in free products of groups
Abstract: We will discuss the Kurosh rank of the intersection of subgroups in free products of groups and a property of groups which turns out to be useful in getting upper bounds for the Kurosh rank and which traces back to Cauchy who proved in 1813 what is now called the Cauchy-Davenport theorem.

Thursday, September 17, 2009

Group Theory Seminar
1:00 pm   in Altgeld Hall 347,  Thursday, September 17, 2009
 Del 
 Edit 
 Copy 
Submitted by kapovitc.
Brent Solie (UIUC Math)
Algorithmic and Genericity Properties of Filling Elements
Abstract: Let F be a free group of finite rank. An element w in F is said to be filling if it has positive translation distance on every very small R-tree on which F acts by isometries. I will present an algorithm that identifies the filling elements in a free group of rank 2 and an algorithm that identifies a certain type of non-filling element in higher rank. I will also give a proof that almost every element of a free group is filling, based directly on the work of Kapovich, Schupp, and Shpilrain.

Thursday, October 1, 2009

Group theory seminar
1:00 pm   in 347 Altgeld Hall,  Thursday, October 1, 2009
 Del 
 Edit 
 Copy 
Submitted by dsrobins.
Derek Robinson (Department of Mathematics, University of Illinois)
The Schur multiplier of a generalized Baumslag-Solitar group
Abstract: A generalized Baumslag-Solitar group (or GBS-group) is the fundamental group of a finite connected graph of groups whose vertex groups are infinite cyclic. It is known that the homology and cohomology of a GBS-group vanish in dimensions 3 and higher. This leaves open the question of dimensions 1 and 2, and in particular the structure of the Schur multiplier of a GBS-group. We will describe a method for computing the multiplier of an arbitrary GBS-group and then give some applications to central extensions by GBS-groups.

Thursday, October 8, 2009

Group Theory Seminar
1:00 pm   in 347 Altgeld Hall,  Thursday, October 8, 2009
 Del 
 Edit 
 Copy 
Submitted by clein.
Chris Leininger (UIUC Math)
Commensurators of of non-free Kleinian groups
Abstract: Work of Margulis shows that a lattice in PSL(2,C) is arithmetic if and only if its commensurators is indiscrete. I'll discuss joint work with Long and Reid in which we consider commensurators of finitely generated Kleinian groups which are NOT lattices.

Thursday, October 15, 2009

Group Theory Seminar
1:00 pm   in Altgeld Hall 347,  Thursday, October 15, 2009
 Del 
 Edit 
 Copy 
Submitted by kapovitc.
Johanna Mangahas (University of Michigan)
"Short-word" pseudo-Anosovs
Abstract: The problem of finding "short-word" pseudo-Anosovs relates to proving effective versions of the Tits alternative for the mapping class group. I'll describe both problems, their relation, and their solutions.

Thursday, October 29, 2009

Group Theory Seminar
1:00 pm   in Altgeld Hall 347,  Thursday, October 29, 2009
 Del 
 Edit 
 Copy 
Submitted by kapovitc.
Nathan Dunfield (UIUC Math)
To Be Announced
Abstract: The talk is cancelled due to the speaker's illness

Thursday, November 5, 2009

Group Theory Seminar
1:00 pm   in Altgeld Hall 347,  Thursday, November 5, 2009
 Del 
 Edit 
 Copy 
Submitted by kapovitc.
Lewis Bowen (Texas A&M)
Free subgroups of lattices
Abstract: Let G be any locally compact, unimodular, metrizable group. The main result of the talk, roughly stated, is that if $F < G$ is any finitely generated free group and $\Gamma < G$ any lattice, then up to a small perturbation and passing to a finite index subgroup, F is a subgroup of $\Gamma$. This result has recently been used by Lackenby, Long and Reid to show that, for cocompact Kleinian groups, LERF implies the Lubotzky-Sarnak conjecture. Another application, due to Lackenby, is that every Kleinian group that contains a finite noncyclic subgroup is either finite, virtually free, or contains a surface subgroup.

Thursday, November 19, 2009

Group Theory Seminar
1:00 pm   in Altgeld Hall 347,  Thursday, November 19, 2009
 Del 
 Edit 
 Copy 
Submitted by kapovitc.
Martin Evans (University of Alabama)
Relation Modules of Infinite Groups.
Abstract: Let A and B be relation modules of a d-generator group G, associated with presentations on $m\geq d$ generators, and let R denote the integral group ring of G. In general A and B are not isomorphic as R-modules although they are STABLY isomorphic. We discuss the minimal rank k such that the direct sum of A and the free R-module of rank k is isomorphic to the direct sum of B and the free R-module of rank k.

Thursday, December 3, 2009

Group Theory Seminar
1:00 pm   in 347 Altgeld Hall,  Thursday, December 3, 2009
 Del 
 Edit 
 Copy 
Submitted by nmd.
David Fisher (Indiana University)
Quasi-isometric embeddings of higher rank symmetric spaces
Abstract: I will describe some results and examples concerning quasi-isometric embeddings of a higher rank irreducible symmetric space X into a higher rank irreducible symmetric space Y. Particularly in the case rk(X) = rk(Y). I will give some conditions under which any such qi embedding is close to an isometric embedding. I will also exhibit explicit embeddings of SL(n, R) into SP(2(n-1), R) which shows that there are qi embeddings that are not close to isometric ones. This is joint work with Kevin Whyte.

Thursday, January 21, 2010

Group Theory Seminar
1:00 pm   in Altgeld Hall 347,  Thursday, January 21, 2010
 Del 
 Edit 
 Copy 
Submitted by kapovitc.
Organizational meeting

Thursday, January 28, 2010

Group Theory Seminar
1:00 pm   in Altgeld Hall 347,  Thursday, January 28, 2010
 Del 
 Edit 
 Copy 
Submitted by kapovitc.
Igor Mineyev (UIUC Math)
The topology and analysis of the Hanna Neumann conjecture
Abstract: We provide several approaches to the Hanna Neumann conjecture using topology and analysis. For the topological part, we define systems of complexes, atomic decomposition of graphs, and other concepts. The analytic part is the use of the classical Murray-von Neumann (!) dimension of Hilbert modules. Special cases and generalizations will be discussed.

Thursday, February 4, 2010

Group Theory Seminar
1:00 pm   in Altgeld Hall 347,  Thursday, February 4, 2010
 Del 
 Edit 
 Copy 
Submitted by kapovich.
Igor Mineyev (UIUC Math)
The topology and analysis of the Hanna Neumann conjecture (continued)
Abstract: We provide several approaches to the Hanna Neumann conjecture using topology and analysis. For the topological part, we define systems of complexes, atomic decomposition of graphs, and other concepts. The analytic part is the use of the classical Murray-von Neumann (!) dimension of Hilbert modules. Special cases and generalizations will be discussed.

Thursday, February 11, 2010

Group Theory Seminar
1:00 pm   in Altgeld Hall 347,  Thursday, February 11, 2010
 Del 
 Edit 
 Copy 
Submitted by kapovitc.
Matt Clay (Allegheny College)
Currents and nonsingular matrices
Abstract: I will show that for n at least 3, given any matrix in GL(n,Z), there is a hyperbolic fully irreducible automorphism of the free group of rank n whose induced action on homology is the given matrix. This is joint work with Alexandra Pettet.

Thursday, March 4, 2010

Group Theory Seminar
1:00 pm   in Altgeld Hall 347,  Thursday, March 4, 2010
 Del 
 Edit 
 Copy 
Submitted by kapovich.
Moon Duchin (University of Michigan)
To Be Announced