A Polynomial Growth Recognition Theorem for Out(F_n)
Gregory Fein (Rutgers)
Abstract: A recognition theorem for Out(F_n) is one that provides a
canonical set of invariants that uniquely determine an outer automorphism
of the free group. By beginning with an analogy to the mapping class group
of a surface and providing several examples and pictures, I'll explain
some problems that arise when attempting a recognition theorem for outer
automorphisms that include periodic behavior, particularly those which
cause word lengths in the free group to grow at most polynomially. I'll
state some results of mine that address these issues in a topological way
and give an idea of the proofs.