Topology Seminar
Friday, November 21, 2003 - 3:30-4:30 p.m.
325 Fayard Hall
| SPEAKER: | Professor John D. McCarthy - Michigan State University |
| TITLE: | Automorphisms of surface braid groups |
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ABSTRACT: |
This talk is on joint work with Elmas Irmak and Nikolai Ivanov. Let S be a closed, orientable, connected surface of genus g. Let n be a positive integer. The n-string surface braid group of S, denoted Bn(S), is the fundamental group of the space of unordered n-tuples of distinct points on S. Let {x1,..., xn} be the chosen basepoint for Bn(S). We prove that every automorphism of Bn(S) is induced by a self-homeomorphism of the pair (S, {x1,..., xn}) provided that g > 1 and n > 2. This result establishes for the relevant surface braid groups what has been previously established for surface mapping class groups and Torelli groups. |