Definition of Casson Invariant

Series
Geometry Topology Student Seminar
Time
Wednesday, April 10, 2019 - 2:00pm for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Hongyi Zhou – Georgia Institute of Technology – hzhou@gatech.edu
Organizer
Surena Hozoori

Casson invariant is defined for the class of oriented integral homology 3-spheres. It satisfies certain properties, and reduce to Rohlin invariant after mod 2. We will define Casson invariant as half of the algebraic intersection number of irreducible representation spaces (space consists of representations of fundamental group to SU(2)), and then prove this definition satisfies the expected properties.