  Inspired by Pansiot's work on substitutions, we prove a similar theorem for
automorphisms of a free group F of finite rank: if a right-infinite word
represents an attracting fixed point of an automorphism of F, the subword
complexity of X is equivalent to n, n log log n, n log n, or n^2. The proof
uses combinatorial arguments analogue to Pansiot's as well as train tracks. We
also define the recurrence complexity of X, and we apply it to laminations. In
particular, we show that attracting laminations have complexity equivalent to
n, n log log n, n log n, or n^2 (to n if the automorphism is fully
irreducible).
