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Organizers |
Global fixed points for centralizers and Morita's Theorem
by
John Franks
Dept. of Mathematics, Nortwestern University
Coauthors: Michael Handel
We prove a global fixed point theorem for the centralizer of a homeomorphism of the two dimensional disk D that has attractor-repeller dynamics on the boundary with at least two attractors and two repellers. As one application, we show that there is a finite index subgroup of the centralizer of a pseudo-Anosov homeomorphism with infinitely many global fixed points. As another application we give an elementary proof of Morita's Theorem, that the mapping class group of a closed surface S of genus g does not lift to the group of diffeormorphisms of S and we improve the lower bound for g from 5 to 3.
Date received: February 12, 2008
Copyright © 2008 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cawk-42.