"The Action of the Torelli Group on a Family of Curve Complexes"







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.