Orientable maps and polynomial invariants of free-by-cyclic groups

We relate the McMullen polynomial of a free-by-cyclic group to its Alexander polynomial. To do so, we introduce the notion of an orientable fully irreducible outer automorphism F and use it to characterize when the homological stretch factor of F is equal to its geometric stretch factor. This is joint work with Spencer Dowdall and Radhika Gupta.