Karen Vogtmann

Finite groups of outer automorphisms of right-angled Artin groups

Right-angled Artin groups interpolate between free groups and free abelian groups, so their outer automorphism groups can be thought of as interpolating between Out(F_n) and GL(n,Z). Both of the latter groups have only a finite number of conjugacy classes of finite subgroups, and these subgroups can be realized as isometries of geometric objects (metric graphs and flat tori respectively). I will explain what we know about finite subgroups of outer automorphisms of general right-angled Artin groups, where the structure of the outer automorphism group depends seriously on the combinatorics of the defining graph. This is joint work with C. Bregman and R. Charney.

(Joint Seminar with Geometry and Topology)