Hyperbolic Handlebody Complements in 3-Manifolds
Colin Adams, Francisco Gomez-Paz, Jiachen Kang, Lukas Krause, Gregory Li, Chloe Marple, Ziwei Tan
TL;DR
The paper proves that any compact orientable 3-manifold $M$ (after capping spherical boundaries and removing torus boundaries) contains genus-$n$ handlebodies whose complements are tg-hyperbolic for any $n\ge 2$, extending Myers’ knot-exterior construction via knotted graph tangles to raise genus. It establishes incompressibility and simplicity of the relevant pieces through explicit fundamental-group calculations and a gluing lemma framework, enabling the assembled handlebody complements to be tg-hyperbolic by Thurston’s theory. The authors show this yields a volume spectrum $v_n^{min}(M)$ and, in a volume-bounds direction, extend the octahedral decomposition to generalized octahedra for spatial graphs in $S^3$ or thickened surfaces, giving explicit upper bounds proportional to crossing number and computing the maximal volume via the ideal, right-angled cuboctahedron. Collectively, the results provide both structural hyperbolicity inside arbitrary 3-manifolds and quantitative volume estimates tied to graph projections, with implications for hyperbolic invariants of non-hyperbolic hosts.
Abstract
Let $M_0$ be a compact and orientable 3-manifold. After capping off spherical boundaries with balls and removing any torus boundaries, we prove that the resulting manifold $M$ contains handlebodies of arbitrary genus such that the closure of their complement is hyperbolic. We then extend the octahedral decomposition to obtain bounds on volume for some of these handlebody complements.
