|January 20||Organizational Meeting||Room 520, 2pm|
|February 3||Victoria Akin, Chicago||Point-pushing in the mapping class group|
|February 10||Jonah Gaster, Boston College||TBA|
|February 17||Sarah Mousley, U. Illinois||TBA|
|February 24||Carolyn Abbott, CUNY and Wisconsin||Universal acylindrical actions|
|March 3||Feng Luo, Rutgers||TBA|
|March 10||Anh Tran, UT Dallas||TBA|
|March 17||No seminar||Spring break|
|March 24||Xinghua Gao, Illinois||TBA|
|March 31||Ilya Kofman, CUNY||TBA|
|April 7||Matthew Stover||TBA|
|April 21||Kevin Kordek, TAMU||TBA|
Victoria Akin, Chicago
Title: Point-pushing in the mapping class group
The point-pushing subgroup of the mapping class group of a surface with a marked point can be considered topologically as the subgroup that pushes the marked point about loops in the surface. Birman, who discovered the point-pushing map, showed that this subgroup is abstractly isomorphic to the fundamental group of the surface, \pi_1(S). We can characterize this point-pushing subgroup algebraically as the only normal subgroup inside of the mapping class group isomorphic to \pi_1(S). This uniqueness allows us to recover a description of the outer automorphism group of the mapping class group.
Jonah Gaster, Boston College
Sarah Mousley, U. Illinois
Carolyn Abbott, CUNY and Wisconsin
Title:Universal acylindrical actions
The class of acylindrically hyperbolic groups, which are groups that admit a certain type of non-elementary action on a hyperbolic space, contains many interesting groups such as non-exceptional mapping class groups and Out(F_n) for n>1. In such a group, a generalized loxodromic element is one that is loxodromic for some acylindrical action of the group on a hyperbolic space. Given a finitely generated group, one can look for an acylindrical action on a hyperbolic space in which all generalized loxodromic elements act loxodromically; such an action is called a universal acylindrical action. I will discuss recent results in the search for universal acylindrical actions, describing a class of groups for which it is always possible to construct such an action as well as an example of a group for which no such action exists.
Feng Luo, Rutgers
Ahn Tran, UT Dallas
Xinghua Gao, Illinois
Ilya Kofman, CUNY
Matthew Stover, Temple
Kevin Kordek, TAMU
Other relevant information.Fall 2016, Spring 2016, Fall 2015, Spring 2015, Fall 2014, Spring 2014, Fall 2013, Spring 2013, Fall 2012, Spring 2012, Fall 2011, 2010/11, Spring 2010, Fall 2009, Spring 2009, Fall 2008, Spring 2008, Fall 2007, Spring 2007, Fall 2006.
- Columbia Symplectic Geometry/Gauge Theory Seminar
- All Columbia Math Dept Seminars
- CUNY Geometry and Topology Seminar
- CUNY Complex Analysis & Dynamics Seminar
- CUNY Magnus Seminar
- Princeton Topology Seminar.