Results 11 to 20 of about 66 (66)
Quasi‐isometric diversity of marked groups
Journal of Topology, Volume 14, Issue 2, Page 488-503, June 2021., 2021 Abstract We use basic tools of descriptive set theory to prove that a closed set S of marked groups has 2ℵ0 quasi‐isometry classes, provided that every non‐empty open subset of S contains at least two non‐quasi‐isometric groups. It follows that every perfect set of marked groups having a dense subset of finitely presented groups contains 2ℵ0 quasi ...
A. Minasyan, D. Osin, S. Witzel
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Calculating the virtual cohomological dimension of the automorphism group of a RAAG
Bulletin of the London Mathematical Society, Volume 53, Issue 1, Page 259-273, February 2021., 2021 Abstract We describe an algorithm to find the virtual cohomological dimension of the automorphism group of a right‐angled Artin group. The algorithm works in the relative setting; in particular, it also applies to untwisted automorphism groups and basis‐conjugating automorphism groups.
Matthew B. Day +2 more
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Cusps, Kleinian groups, and Eisenstein series
Forum of Mathematics, Sigma, 2023 We study the Eisenstein series associated to the full rank cusps in a complete hyperbolic manifold. We show that given a Kleinian group $\Gamma
Beibei Liu, Shi Wang
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On subset sum problem in branch groups [PDF]
Groups, Complexity, Cryptology, 2020 We consider a group-theoretic analogue of the classic subset sum problem. In this brief note, we show that the subset sum problem is NP-complete in the first Grigorchuk group.
Andrey Nikolaev, Alexander Ushakov
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Injectivity results for coarse homology theories
Proceedings of the London Mathematical Society, Volume 121, Issue 6, Page 1619-1684, December 2020., 2020 Abstract We show injectivity results for assembly maps using equivariant coarse homology theories with transfers. Our method is based on the descent principle and applies to a large class of linear groups or, more generally, groups with finite decomposition complexity.
Ulrich Bunke +3 more
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Curve graphs for Artin–Tits groups of type B, A∼ and C∼ are hyperbolic
Transactions of the London Mathematical Society, 2021 The graph of irreducible parabolic subgroups is a combinatorial object associated to an Artin–Tits group A defined so as to coincide with the curve graph of the (n+1)‐times punctured disk when A is Artin's braid group on (n+1) strands.
Matthieu Calvez +1 more
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Homotopy type of the complex of free factors of a free group
Proceedings of the London Mathematical Society, Volume 121, Issue 6, Page 1737-1765, December 2020., 2020 Abstract We show that the complex of free factors of a free group of rank n⩾2 is homotopy equivalent to a wedge of spheres of dimension n−2. We also prove that for n⩾2, the complement of (unreduced) Outer space in the free splitting complex is homotopy equivalent to the complex of free factor systems and moreover is (n−2)‐connected.
Benjamin Brück, Radhika Gupta
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The Asymptotic Statistics of Random Covering Surfaces
Forum of Mathematics, Pi, 2023 Let $\Gamma _{g}$ be the fundamental group of a closed connected orientable surface of genus $g\geq 2$ . We develop a new method for integrating over the representation space $\mathbb {X}_{g,n}=\mathrm {Hom}(\Gamma _{g},S_{n})$ , where
Michael Magee, Doron Puder
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Finite‐dimensional approximation properties for uniform Roe algebras
Journal of the London Mathematical Society, Volume 102, Issue 2, Page 623-644, October 2020., 2020 Abstract We study property A for metric spaces X with bounded geometry introduced by Guoliang Yu. Property A is an amenability‐type condition, which is less restrictive than amenability for groups. The property has a connection with finite‐dimensional approximation properties in the theory of operator algebras. It has been already known that property A
Hiroki Sako
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Growth functions for some uniformly amenable groups
Open Mathematics, 2017 We present a simple constructive proof of the fact that every abelian discrete group is uniformly amenable. We improve the growth function obtained earlier and find the optimal growth function in a particular case.
Dronka Janusz +3 more
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