A description of auto-fixed subgroups in a free group
arXiv:math/0306380
Abstract
Let be a finitely generated free group. By using Bestvina-Handel theory, as well as some further improvements, the eigengroups of a given automorphism of (and its fixed subgroup among them) are globally analyzed and described. In particular, an explicit description of all subgroups of which occur as the fixed subgroup of some automorphism is given.
41 pages