Group Actions Seminar: Holt, Thomas

I have renamed the Infinite Groups Seminar to the Group Actions Seminar.  

Our first meeting for 2012 will be held at the University of Sydney on Monday 20
February, with Derek Holt and Anne Thomas speaking.  Details are below.  

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Date: Monday 20 February 

Time: 12 noon 

Location: Room 830, Carslaw Building, University of Sydney 

Speaker: Derek Holt (University of Warwick) 

Title: Automaticity of Artin groups 

Abstract: 

After a brief resumee of the definition and basic properties of automatic groups, we
discuss the question of which Artin groups are automatic.  This has been proved for
various types of Artin groups by Charney, Hermiller and Meier, Peiffer, Brady and
McCammond, and others.  We report on recent work with Sarah Rees that certain other
types of Artin groups, including all of those of large-type, are automatic.  

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Date: Monday 20 February 

Time: 2:30pm 

Location: Room 829 (Access Grid Room), Carslaw Building, University of Sydney 

Speaker: Anne Thomas (University of Sydney) 

Title: Divergence in right-angled Coxeter groups 

Abstract: 

The divergence of a pair of geodesics emanating from a point in a metric space is a
measure of how quickly they are moving away from each other.  In Euclidean space
divergence is linear, while in hyperbolic space divergence is exponential.  Gersten used
this idea to define a quasi-isometry invariant for groups, which has been investigated
for classes of groups including 3-manifold groups, mapping class groups and right-angled
Artin groups.  I will discuss joint work with Pallavi Dani on divergence in the class of
right-angled Coxeter groups.  

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