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Related papers: Comparison of equivariant cohomological dimensions

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Let $\pi$ be a group equipped with an action of a second group $G$ by automorphisms. We define the equivariant cohomological dimension ${\sf cd}_G(\pi)$, the equivariant geometric dimension ${\sf gd}_G(\pi)$, and the equivariant…

Algebraic Topology · Mathematics 2020-04-24 Mark Grant , Ehud Meir , Irakli Patchkoria

We give the characterisation of cohomological dimension of group homomorphisms. In particular, we show the analogue of the Stallings-Swan theorem in the case of group epimorphisms.

Algebraic Topology · Mathematics 2025-09-19 Nursultan Kuanyshov

We define and study an equivariant version of Farber's topological complexity for spaces with a given compact group action. This is a special case of the equivariant sectional category of an equivariant map, also defined in this paper. The…

Algebraic Topology · Mathematics 2014-10-01 Hellen Colman , Mark Grant

Bounded-cohomological dimension of groups is a relative of classical cohomological dimension, defined in terms of bounded cohomology with trivial coefficients instead of ordinary group cohomology. We will discuss constructions that lead to…

Group Theory · Mathematics 2015-09-09 Clara Loeh

We prove that the Bredon cohomological dimension and the virtual cohomological dimension coincide for groups that admit a cocompact model for $\underline{E}G$ and satisfy properties (M) and (NM). Among the examples of groups satisfying…

Group Theory · Mathematics 2020-10-08 Luis Jorge Sánchez Saldaña

We consider smooth actions of totally disconnected groups on simplicial complexes and compare different equivariant cohomology groups associated to such actions. Our main result is that the bivariant equivariant cohomology theory introduced…

K-Theory and Homology · Mathematics 2007-05-23 Christian Voigt

This is a further investigation of our approach to group actions in homological algebra in the settings of homology of {\Gamma}-simplicial groups, particularly of {\Gamma}-equivariant homology and cohomology of {\Gamma}-groups. This…

K-Theory and Homology · Mathematics 2021-07-26 Hvedri Inassaridze

In this paper, we introduce Mackey functors for a t.d.l.c. group and define the cohomological dimension of this group over the Mackey category. We then compare this dimension to the rational discrete cohomological dimension defined by…

Group Theory · Mathematics 2026-01-21 Ilaria Castellano , Nadia Mazza , Brita Nucinkis

We investigate strictly developable simple complexes of groups with arbitrary local groups, or equivalently, group actions admitting a strict fundamental domain. We introduce a new method for computing the cohomology of such groups. We also…

Group Theory · Mathematics 2022-10-10 Nansen Petrosyan , Tomasz Prytuła

There are (at least) two different approaches to define equivariant analogue of the Euler charateristic for a space with a finite group action. The first one defines it as an element of the Burnside ring of the group. The second approach…

Algebraic Geometry · Mathematics 2016-05-11 S. M. Gusein-Zade , I. Luengo , A. Melle-Hernández

For groups with a uniform bound on the length of chains of finite subgroups, we study the relationship between the Bredon cohomological dimension for proper actions and the notions of cohomological dimension one obtains by restricting the…

Algebraic Topology · Mathematics 2015-03-03 Dieter Degrijse

We generalize several comparison results between algebraic, semi-topological and topological K-theories to the equivariant case with respect to a finite group.

K-Theory and Homology · Mathematics 2013-08-21 Jeremiah Heller , Jens Hornbostel

For a discrete group $\Gamma$ satisfying some finiteness conditions we give a Bredon projective resolution of the trivial module in terms of projective covers of the chain complex associated to certain posets of subgroups. We use this to…

Group Theory · Mathematics 2012-02-27 Conchita Martínez-Pérez

We present a new approach to equivariant version of the topological complexity, called a symmetric topological complexity. It seems that the presented approach is more adequate for the analysis of an impact of symmetry on the the motion…

Algebraic Topology · Mathematics 2015-06-12 Wojciech Lubawski , Wacław Marzantowicz

Let $G$ be a group that admits a cocompact classifying space for proper actions $X$. We derive a formula for the Bredon cohomological dimension for proper actions of $G$ in terms of the relative cohomology with compact support of certain…

Algebraic Topology · Mathematics 2015-03-03 Dieter Degrijse , Conchita Martinez-Perez

In this paper, motivated by a problem posed by Barry Mazur, we show that for smooth projective varieties over the rationals, the odd cohomology groups of degree less than or equal to the dimension can be modeled by the cohomology of an…

Algebraic Geometry · Mathematics 2019-02-20 Jeff Achter , Sebastian Casalaina-Martin , Charles Vial

We compute the equivariant cohomology of complex projective spaces associated to finite-dimensional representations of $C_2$, using ordinary cohomology graded on representations of the fundamental groupoid, with coefficients in the Burnside…

Algebraic Topology · Mathematics 2022-05-17 Steven R. Costenoble , Thomas Hudson , Sean Tilson

We introduce a version of Farber's topological complexity suitable for investigating mechanical systems whose configuration spaces exhibit symmetries. Our invariant has vastly different properties to the previous approaches of Colman-Grant,…

Algebraic Topology · Mathematics 2018-01-09 Zbigniew Błaszczyk , Marek Kaluba

We build a bridge between geometric group theory and topological dynamical systems by establishing a dictionary between coarse equivalence and continuous orbit equivalence. As an application, we give conceptual explanations for previous…

Group Theory · Mathematics 2017-04-19 Xin Li

We consider the semi-direct products $G=\mathbb Z^2\rtimes GL_2(\mathbb Z), \mathbb Z^2\rtimes SL_2(\mathbb Z)$ and $\mathbb Z^2\rtimes\Gamma(2)$ (where $\Gamma(2)$ is the congruence subgroup of level 2). For each of them, we compute both…

Operator Algebras · Mathematics 2023-11-28 Ramon Flores , Sanaz Pooya , Alain Valette
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