Hyperbolic topology and bounded locally homeomorphic quasiregular mappings in 3-space

TL;DR

This paper introduces a new class of bounded locally homeomorphic quasiregular mappings in the 3-ball, constructed via hyperbolic 4-manifolds, addressing longstanding problems in the field.

Contribution

It constructs novel quasiregular mappings using hyperbolic 4-manifolds and group actions, linking 3D quasiregular mappings to hyperbolic geometry and cobordisms.

Findings

Constructed bounded locally homeomorphic quasiregular mappings in the 3-ball.

Linked these mappings to hyperbolic 4-manifolds and their fundamental groups.

Addressed longstanding open problems in quasiregular mapping theory.

Abstract

We use our new type of bounded locally homeomorphic quasiregular mappings in the unit 3-ball to address long standing problems for such mappings. The construction of such mappings comes from our construction of non-trivial compact 4-dimensional cobordisms $M$ with symmetric boundary components and whose interiors have complete 4-dimensional real hyperbolic structures. Such bounded locally homeomorphic quasiregular mappings are defined in the unit 3-ball $B^3\subset \mathbb{R}^3$ as mappings equivariant with the standard conformal action of uniform hyperbolic lattices $\Gamma\subset \operatorname{Isom} H^3$ in the unit 3-ball and with its discrete representation $G=\rho(\Gamma)\subset \operatorname{Isom} H^4 $. Here $G$ is the fundamental group of our non-trivial hyperbolic 4-cobordism $M=(H^4\cup\Omega(G))/G$ and the kernel of the homomorphism $\rho\!:\! \Gamma\rightarrow G$ is a free group $F_3$ on three generators.