Diffeomorphism groups of 3-dim handlebodies and Batalin-Vilkovisky graph homology
Jeffrey Giansiracusa (University of Oxford)
Monday 19th April, 2010 16:00-17:00 Mathematics Building, room 204
From the work of Kontsevich and others we know that certain chain complexes made from graphs, with the differential given by edge contractions, compute various interesting things such as the cohomology of the groups of outer automorphisms of free groups and moduli spaces of curves. I will discuss how the cohomology of the handlebody subgroups of mapping class groups is computed by a graph complex with coefficients in the Batalin-Vilkovisky operad. A key component is the formality of the framed little 2-discs as a cyclic operad.