Geometry Topology Student Seminar
Wednesday, October 30, 2013 - 14:05
1 hour (actually 50 minutes)
Let MCG(g) be the mapping class group of a surface of genus g. For sufficiently large g, the nth homology (and cohomology) group of MCG(g) is independent of g. Hence we say that the family of mapping class groups satisfies homological stability. Symmetric groups and braid groups also satisfy homological stability, as does the family of moduli spaces of certain higher dimensional manifolds. The proofs of homological stability for most families of groups and spaces follow the same basic structure, and we will sketch the structure of the proof in the case of the mapping class group.