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Related papers: Realizations and properties of $3$-spherical Curti…

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We classify all non-collapsing Curtis-Tits and Phan amalgams with $3$-spherical diagram over all fields. In particular, we show that amalgams with spherical diagram are unique, a result required by the classification of finite simple…

Group Theory · Mathematics 2016-11-04 Rieuwert J. Blok , Corneliu G. Hoffman , Sergey V. Shpectorov

In a previous paper we define a Curtis-Tits group as a certain generalization of a Kac-Moody group. We distinguish between orientable and non-orientable Curtis-Tits groups and identify all orientable Curtis-Tits groups as Kac-Moody groups…

Group Theory · Mathematics 2015-10-08 Rieuwert J. Blok , Corneliu Hoffman

We construct several series of explicit presentations of infinite hyperbolic groups enjoying Kazhdan's property (T). Some of them are significantly shorter than the previously known shortest examples. Moreover, we show that some of those…

Group Theory · Mathematics 2021-01-05 Pierre-Emmanuel Caprace , Marston Conder , Marek Kaluba , Stefan Witzel

A group is SimpHAtic if it acts geometrically on a simply connected simplicially hereditarily aspherical (SimpHAtic) complex. We show that finitely presented normal subgroups of the SimpHAtic groups are either: finite, or of finite index,…

Group Theory · Mathematics 2021-09-29 Damian Osajda

The goal of this mostly expository paper is to present several candidates for hyperbolic structures on irreducible Artin-Tits groups of spherical type and to elucidate some relations between them. Most constructions are algebraic analogues…

Geometric Topology · Mathematics 2019-08-29 Matthieu Calvez , Bert Wiest

The classification of Curtis-Tits amalgams with {connected}, triangle free, simply-laced diagram over a field of size at least $4$ was completed in~\cite{BloHof2014b}. Orientable amalgams are those arising from applying the Curtis-Tits…

Group Theory · Mathematics 2015-11-24 Rieuwert J. Blok , Corneliu G. Hoffman

In this paper we show the statement in the title. To any Garside group of finite type, Wiest and the author associated a hyperbolic graph called the \emph{additional length graph} and they used it to show that central quotients of…

Group Theory · Mathematics 2020-10-27 Matthieu Calvez

We present a new notion of non-positively curved groups: the collection of discrete countable groups acting (AU-)acylindrically on finite products of $\delta$-hyperbolic spaces with general type factors. Inspired by the classical theory of…

Group Theory · Mathematics 2025-12-30 Sahana Balasubramanya , Talia Fernos

We present a new notion of non-positively curved groups: the collection of discrete countable groups acting (AU-)acylindrically on finite products of $\delta$-hyperbolic spaces with general type factors and associated subdirect products.…

Group Theory · Mathematics 2025-12-29 Sahana Balasubramanya , Talia Fernos

Using the construction of a nonorientable Curtis-Tits group of type $\tilde A_n$, we obtain new explicit families of expander graphs of valency five for unitary groups over finite fields.

Group Theory · Mathematics 2011-10-31 Rieuwert Blok , Corneliu Hoffman , Alina Vdovina

Following previous work of the second author, we establish more properties of groups of circle homeomorphisms which admit invariant laminations. In this paper, we focus on a certain type of such groups-so-called pseudo-fibered groups, and…

Geometric Topology · Mathematics 2020-02-24 Juan Alonso , Hyungryul Baik , Eric Samperton

A celebrated theorem of Curtis and Tits on groups with finite BN-pair shows that roughly speaking these groups are determined by their local structure. This result was later extended to Kac-Moody groups by P.~Abramenko and B.~M\"uhlherr.…

Group Theory · Mathematics 2010-10-05 Rieuwert Blok , Corneliu Hoffman

We show that, in an Artin-Tits group of spherical type, the intersection of two parabolic subgroups is a parabolic subgroup. Moreover, we show that the set of parabolic subgroups forms a lattice with respect to inclusion. This extends to…

Group Theory · Mathematics 2019-06-20 María Cumplido , Volker Gebhardt , Juan González-Meneses , Bert Wiest

It is conjectured that the central quotient of every irreducible Artin group is either virtually cyclic or acylindrically hyperbolic. We prove this conjecture for Artin groups associated to triangle-free graphs and Artin groups of large…

Group Theory · Mathematics 2020-10-29 Motoko Kato , Shin-ichi Oguni

Charney and Morris-Wright showed acylindrical hyperbolicity of Artin groups of infinite type associated with graphs that are not joins, by studying clique-cube complexes and actions on them. In this paper, by developing their study and…

Geometric Topology · Mathematics 2023-03-14 Motoko Kato , Shin-ichi Oguni

Let k=F_q be a finite field of even characteristic. We obtain in this paper a complete classification, up to k-isomorphism, of non singular quartic plane curves defined over k. We find explicit rational normal models and we give closed…

Number Theory · Mathematics 2007-05-23 Enric Nart , Christophe Ritzenthaler

We show the existence of group-theoretic sections of the "etale-by-geometrically abelian" quotient of the arithmetic fundamental group of hyperbolic curves over $p$-adic local fields relative to a proper and flat model which are…

Number Theory · Mathematics 2015-10-26 Mohamed Saidi

Charney and Morris-Wright showed acylindrical hyperbolicity of Artin groups of infinite type associated with graphs that are not joins, by studying clique-cube complexes and the actions on them. The authors developed their study and…

Group Theory · Mathematics 2025-06-26 Motoko Kato , Shin-ichi Oguni

We prove that acylindrically hyperbolic groups are monotileable. That is, every finite subset of the group is contained in a finite tile. This provides many new examples of monotileable groups, and progress on the question of whether every…

Group Theory · Mathematics 2026-05-14 Joseph MacManus , Lawk Mineh

We show that any group that is hyperbolic relative to virtually nilpotent subgroups, and does not admit peripheral splittings, contains a quasi-isometrically embedded copy of the hyperbolic plane. In natural situations, the specific…

Group Theory · Mathematics 2020-11-09 John M. Mackay , Alessandro Sisto
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