Subgroup tameness conjecture for hyperbolic mapping tori of free groups

About 1 year old · traced to

Let F\mathbb{F} be a finitely generated free group and let ψ→F\psi\to \mathbb{F} be a fully irreducible monomorphism, meaning that no proper nontrivial finitely generated free factor is mapped into a conjugate of itself by a positive power of ψ\psi. Set G=M(ψ)G=M(\psi) and assume that GG is hyperbolic. For a finitely generated subgroup H⩽GH\leqslant G, a fibre subgroup is one arising from an automorphism of a finite-index mapping-torus subgroup, and a semi-fibre subgroup is the analogous subgroup arising from a proper monomorphism. Subgroup tameness conjecture. Either HH is a fibre or semi-fibre subgroup of a finite-index subgroup of GG, or HH is quasi-convex. This is the proposed analogue of the subgroup tameness theorem for hyperbolic 3-manifold groups; the source attributes it to an AIM workshop and Abdenbi–Wise, and gives no resolution.

References

Primary source

Marco Linton, “The geometry of subgroups of mapping tori of free groups”, arXiv:2510.03145 (2025).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.