Sam Tertooy

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20172026

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4 papers · 2 filters

math.GR2026

Taming Reidemeister zeta functions on virtually polycyclic groups

Sam Tertooy

We prove a formula for Reidemeister numbers of virtually polycyclic groups that generalises known formulas for finite groups and torsion-free virtually polycyclic groups. Based on…

math.GR2026

A Hirsch length inequality

Sam Tertooy

Let $H$ and $K$ be subgroups of a virtually polycyclic group $G$ . We prove the Hirsch length inequality $h (H) + h (K) \leq h (H \cap K) + h (G) .$ We show that equality holds when the num…

math.GR2026

Class numbers and nilpotent subgroups of $PGL (2, q)$

Sam Tertooy

We show that for certain odd prime powers $q$ , the number of conjugacy classes of $PGL (2, q)$ is greater than the order of its largest nilpotent subgroup. This answers nega…

math.GR2026

Bi-twisted conjugacy in finite groups

Pieter Senden, Sam Tertooy

We provide two alternative ways to determine the number of bi-twisted conjugacy classes in a finite group: one using irreducible characters and one using ordinary conjugacy classes…

Taming Reidemeister zeta functions on virtually polycyclic groups

A Hirsch length inequality

Class numbers and nilpotent subgroups of PGL(2,q)

Bi-twisted conjugacy in finite groups

Class numbers and nilpotent subgroups of $PGL (2, q)$