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  5. 2026

Geometric Group Theory

Icon: calendar GGT Session Talk #7.2 | 2026 Jul 15 from 11:00AM to 11:25AM (Zagreb) | B3-17

Subevent of GGT Session #7

‟Algebraic fibrations, hyperbolic Coxeter groups and a hidden icosahedron.” by Giovanni Italiano, Matteo Migliorini, Andrew Ng

Abstract:

A group is said to algebraically fibre if it admits an epimorphism onto $\mathbb{Z}$ whose kernel satisfies suitable finiteness properties, such as finite generation or finite presentability.

The study of algebraic fibrations of hyperbolic groups has been a major theme in geometric group theory over the past two decades, motivated in part by the virtual fibering conjecture for odd-dimensional hyperbolic manifolds. Recently, Lafont, Minemyer, Sorcar, Stover, and Wells constructed, for every $d \geq 2$, a $d$-dimensional hyperbolic group admitting an algebraic fibration with finitely generated kernel.

We strengthen this result by showing that, for every $d \geq 3$, there exists a $d$-dimensional hyperbolic group admitting an algebraic fibration whose kernel is finitely presented.

Our construction combines right-angled Coxeter groups and Bestvina–Brady theory with a new collar-coning procedure inspired by a family of polytopes introduced by Löbell in the 1930s.

This is joint work with M. Migliorini and A. Ng.