On Automorphisms of the Hyperelliptic Torelli Group

Series
Geometry Topology Seminar
Time
Monday, February 28, 2011 - 2:05pm for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Leah Childers – Pittsburg State U
Organizer
Dan Margalit
We will discuss the structure of the symmetric (or hyperelliptic) Torelli group. More specifically, we will investigatethe group generated by Dehn twists about symmetric separating curvesdenoted by H(S). We will show that Aut(H(S)) is isomorphic to the symmetricmapping class group up to the hyperelliptic involution. We will do this bylooking at the natural action of H(S) on the symmetric separating curvecomplex and by giving an algebraic characterization of Dehn twists aboutsymmetric separating curves.