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In this paper, we introduce a notion of stable coarse algebras for metric spaces with bounded geometry, and formulate the twisted coarse Baum--Connes conjecture with respect to stable coarse algebras. We prove permanence properties of this…

Operator Algebras · Mathematics 2026-05-05 Jintao Deng , Ryo Toyota

We prove that the Connes embedding problem is stable under graph products.

Operator Algebras · Mathematics 2020-02-17 Martijn Caspers

A family of permutations (\mathcal{A} \subset S_{n}) is said to be (t)-\textit{intersecting} if any two permutations in (\mathcal{A}) agree on at least (t) points, i.e. for any (\sigma, \pi \in \mathcal{A}), (|\{i \in [n]:…

Combinatorics · Mathematics 2009-08-19 David Ellis

We construct a hyperbolic group with a finitely presented subgroup, which has infinitely many conjugacy classes of finite-order elements. We also use a version of Morse theory with high dimensional horizontal cells and use handle…

Group Theory · Mathematics 2009-05-04 Noel Brady , Matt Clay , Pallavi Dani

We prove a homological stability theorem for the subgroup of the mapping class group acting as the identity on some fixed portion of the first homology group of the surface. We also prove a similar theorem for the subgroup of the mapping…

Geometric Topology · Mathematics 2023-11-15 Andrew Putman

We introduce a new quasi-isometry invariant of 2-dimensional right-angled Coxeter groups, the hypergraph index, that partitions these groups into infinitely many quasi-isometry classes, each containing infinitely many groups. Furthermore,…

Geometric Topology · Mathematics 2019-06-26 Ivan Levcovitz

In this paper homology stability for unitary groups over a ring with finite unitary stable rank is established. Homology stability of symplectic groups and orthogonal groups appears as a special case of our results.

K-Theory and Homology · Mathematics 2007-05-23 Behrooz Mirzaii , Wilberd van der Kallen

We classify instances of quantum pseudo-telepathy in the graph isomorphism game, exploiting the recently discovered connection between quantum information and the theory of quantum automorphism groups. Specifically, we show that graphs…

Quantum Physics · Physics 2019-05-14 Benjamin Musto , David Reutter , Dominic Verdon

We show that the fundamental groups of any two closed irreducible non-geometric graph-manifolds are quasi-isometric. This answers a question of Kapovich and Leeb. We also classify the quasi-isometry types of fundamental groups of…

Geometric Topology · Mathematics 2010-04-13 Jason A. Behrstock , Walter D. Neumann

We give a simple algorithm that enables us to determine whether a subgroup of finite index of the Hecke group is normal.

Number Theory · Mathematics 2015-01-06 Cheng Lien Lang , Mong Lung Lang

We prove the transversality result necessary for defining local Morse chain complexes with finite cyclic group symmetry. Our arguments use special regularized distance functions constructed using classical covering lemmas, and an inductive…

Symplectic Geometry · Mathematics 2018-09-18 Doris Hein , Umberto L. Hryniewicz , Leonardo Macarini

We show that Wise's power alternative is stable under certain group constructions, use this to prove the power alternative for new classes of groups, and recover known results from a unified perspective. For groups acting on trees, we…

Group Theory · Mathematics 2025-12-03 Mark Hagen , Alexandre Martin , Giovanni Sartori

In this note, we consider the notion of what we call recognizing spaces for stable subgroups of a given group. When a group $G$ is a mapping class group or right-angled Artin group, it is known that a subgroup is stable exactly when the…

Group Theory · Mathematics 2025-06-26 Sahana Balasubramanya , Marissa Chesser , Alice Kerr , Johanna Mangahas , Marie Trin

A discrete group is matricially stable if every function from the group to a complex unitary group that is "almost multiplicative" in the point-operator norm topology is "close" to a genuine unitary representation. It follows from a recent…

Group Theory · Mathematics 2024-03-25 Forrest Glebe

Consider a holomorphic torus action on vector bundles over a complex manifold which lifts to a holomorphic vector bundle. When the connected components of the fixed-point set are partially ordered, we construct, using sheaf-theoretical…

Algebraic Geometry · Mathematics 2007-05-23 Siye Wu

We define a quasihomomorphism from braid groups to the concordance group of knots and examine its properties and consequences of its existence. In particular, we provide a relation between the stable four ball genus in the concordance group…

Geometric Topology · Mathematics 2015-11-25 Michael Brandenbursky , Jarek Kędra

A probability-measure-preserving action of a countable group is called stable if its transformation-groupoid absorbs the ergodic hyperfinite equivalence relation of type II_1 under direct product. We show that for a countable group G and…

Dynamical Systems · Mathematics 2017-05-18 Yoshikata Kida

We investigate the existence of stationary fronts in a coupled system of two sine-Gordon equations with a smooth, "hat-like" spatial inhomogeneity. The spatial inhomogeneity corresponds to a spatially dependent scaling of the sine-Gordon…

Dynamical Systems · Mathematics 2020-01-08 Jacob Brooks , Gianne Derks , David J. B. Lloyd

We discuss a general framework of monotone skew-product semiflows under a connected group action. In a prior work, a compact connected group $G$-action has been considered on a strongly monotone skew-product semiflow. Here we relax the…

Dynamical Systems · Mathematics 2012-01-30 Feng Cao , Mats Gyllenberg , Yi Wang

We formulate a new criterion of the asymptotic stability for some non-equicontinuous Markov semigroups, the so-called eventually continuous semigroups. In particular, we provide a non-equicontinuous Markov semigroup example with essential…

Probability · Mathematics 2025-03-05 Fuzhou Gong , Yong Liu , Yuan Liu , Ziyu Liu