D. Gaboriau et al., A DENDROLOGICAL PROOF OF THE SCOTT CONJECTURE FOR AUTOMORPHISMS OF FREE GROUPS, Proceedings of the Edinburgh Mathematical Society, 41, 1998, pp. 325-332
Let alpha be an automorphism of a free group of rank n. The Scott conj
ecture, proved by Bestvina-Handel, asserts that the fixed subgroup of
alpha has rank at most n. We give a short alternative proof of this re
sult using R-trees.