T. Marquis

activity

20182025

collaborators

8 papers

math.GR2025

Presentation and uniqueness of Kac-Moody groups over local rings

Timothée Marquis, Bernhard Mühlherr

To any generalised Cartan matrix (GCM) $A$ and any ring $R$ , Tits associated a Kac-Moody group $G_{A} (R)$ defined by a presentation à la Steinberg. For a domain $R$ with f…

math.GR2025

Describing the nub in maximal Kac-Moody groups

Sebastian Bischof, Timothée Marquis

Let $G$ be a totally disconnected locally compact (tdlc) group. The contraction group $con (g)$ of an element $g \in G$ is the set of all $h \in G$ such that $g^n h g^{-n} \t…

math.GR2025

Stable reflection length in Coxeter groups

Francesco Fournier-Facio, Marco Lotz, Timothée Marquis

We introduce stable reflection length in Coxeter groups, as a way to study the asymptotic behaviour of reflection length. This creates connections to other well-studied stable leng…

math.GR2024

Amalgams of rational unipotent groups and residual nilpotence

Pierre-Emmanuel Caprace, Timothée Marquis

We provide sufficient conditions for a free amalgamated product of torsionfree nilpotent groups to be residually nilpotent. We also characterise the residual nilpotence of certain…

math.GR2023

Minicourse on Kac-Moody groups

Timothée Marquis

These are informal lecture notes for a three-hour minicourse on Kac-Moody groups, given at the workshop "Kac-Moody geometry" in July 2023 in Kiel. They provide a concise overview o…

math.GR2019

Hyperfiniteness of boundary actions of hyperbolic groups

Timothée Marquis, Marcin Sabok

We prove that for every finitely generated hyperbolic group $G$ , the action of $G$ on its Gromov boundary induces a hyperfinite equivalence relation.