September 2017 |

4:00 pm Monday, October 23, 2017 Topology Seminar: Free products in Diff(S^1)by Sam Kim (Seoul National University) in HBH 427- We prove that the class of subgroups of Diff^r(S^1) is not closed under taking free products for each 2<= r <=infinity. More specifically, if G is finitely generated non-virtually-abelian group, then (G x Z) * Z does not embed into Diff^r(S^1). We then complete the classification of RAAGs embeddable in Diff^r(S^1), answering a question of Kharlamov (in a paper of M. Kapovich). This is a joint work with Thomas Koberda.
Submitted by neil.fullarton@rice.edu |