skip to content
 

The borders of Outer space

Presented by: 
Karen Vogtmann University of Warwick, Cornell University
Date: 
Friday 23rd June 2017 - 14:30 to 15:30
Venue: 
INI Seminar Room 1
Abstract: 
Outer space is an analog for the group Out(F_n) of the symmetric space associated to an algebraic group.  Motivated by work of Borel and Serre, Bestvina and Feighn defined a bordification of Outer space; this is an enlargement of outer space which is highly-connected at infinity and on which the action of Out(F_n) extends, with compact quotient. We realize this bordification as a deformation retract of Outer space instead of an extension.  We use this to give a simpler connectivity proof, and to give a description of the boundary nicely analogous to that of the Borel-Serre boundary of a symmetric space. This is joint work with Kai-Uwe Bux and Peter Smillie.
The video for this talk should appear here if JavaScript is enabled.
If it doesn't, something may have gone wrong with our embedded player.
We'll get it fixed as soon as possible.
University of Cambridge Research Councils UK
    Clay Mathematics Institute London Mathematical Society NM Rothschild and Sons