"The Action of the Torelli Group on a Family of Curve
Complexes"
By
Abstract: Curve
complexes have traditionally been used to study the mapping class group of a
surface. For the Torelli group, i.e. the subgroup of
the mapping class group that acts trivially on homology, it is necessary to
think about group actions in very different ways, for reasons that will be
explained. In this talk it will be shown that a family of oriented curve
complexes give a combinatorial description of an invariant of the Torelli group - the Johnson homomorphism.
Date: Monday, October 19, 2015
Time: 13.40 – 14:30
Place: Mathematics Seminar Room,
SA-141
All are most cordially invited.
Tea and cookies will be served after the talk.