Relatively irreducible free subroups in Out($\mathbb{F}$)
Abstract
We prove that given a finite rank free group of rank and two exponentially growing outer automorphisms and with dual lamination pairs and associated to them, and given a free factor system with co-edge number , each preserving , so that the pair is independent relative to , then there , such that for any integer , the group is a free group of rank 2, all of whose non-trivial elements except perhaps the powers of and their conjugates, are fully irreducible relative to with a lamination pair which fills relative to . In addition if both are non-geometric then this lamination pair is also non-geometric. We also prove that the extension groups induced by such subgroups will be relatively hyperbolic under some natural conditions.
Cite
@article{arxiv.1802.05705,
title = {Relatively irreducible free subroups in Out($\mathbb{F}$)},
author = {Pritam Ghosh},
journal= {arXiv preprint arXiv:1802.05705},
year = {2018}
}
Comments
Minor corrections, notation changes, updated references. Some proofs rewritten for better readability