Dan Margalit (GA Tech) - Mapping class groups in complex dynamics
Опубликовано: 29 Июль 2026
на канале: 2017-2018 Warwick EPSRC Symposium on Geometry, Topology and Dynamics in Low Dimensions
на канале: 2017-2018 Warwick EPSRC Symposium on Geometry, Topology and Dynamics in Low Dimensions
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Geometry of Teichmüller space and mapping class groups
13 April 2018
Abstract: A polynomial can be thought of as a branched cover of the Riemann sphere. Given a branched cover of the sphere, we can ask if it is equivalent to a polynomial, and if so, which one. In 2006, Bartholdi and Nekrashevych gave an algebraic solution to this problem and applied their method to explicitly solve the twisted rabbit problem of Douady and Hubbard. With Belk, Lanier, and Winarski, we give a purely topological method that closely mirrors the modern theories of mapping class groups and outer automorphisms of free groups.