Digraphs and cycle polynomials for free-by-cyclic groups

Yael Algom-Kfir, Eriko Hironaka, Kasra Rafi

Let $ϕ\in \mbox{Out}(F_n)$ be a free group outer automorphism that can be represented by an expanding, irreducible train-track map. The automorphism $\varphi$ determines a free-by-cyclic…