A Guide to Equivariant Parametrized Cohomology

Fuente: arXiv
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Autores principales: Beaudry, Agnès, Lewis, Chloe, May, Clover, Pauli, Sabrina, Tatum, Elizabeth
Formato: Preprint
Publicado: 2024
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author Beaudry, Agnès
Lewis, Chloe
May, Clover
Pauli, Sabrina
Tatum, Elizabeth
author_facet Beaudry, Agnès
Lewis, Chloe
May, Clover
Pauli, Sabrina
Tatum, Elizabeth
contents This article investigates equivariant parametrized cellular cohomology, a cohomology theory introduced by Costenoble-Waner for spaces with an action by a compact Lie group $G$. The theory extends the $RO(G)$-graded cohomology of a $G$-space $B$ to a cohomology graded by $RO(ΠB)$, the representations of the equivariant fundamental groupoid of $B$. This paper is meant to serve as a guide to this theory and contains some new computations. We explain the key ingredients for defining parametrized cellular cohomology when $G$ is a finite group, with particular attention to the case of the cyclic group $G=C_2$. We compute some examples and observe that $RO(ΠB)$ is not always free. When $G$ is the trivial group, we explain how to identify equivariant parametrized cellular cohomology with cellular cohomology in local coefficients. Finally, we illustrate the theory with some new computations of parametrized cellular cohomology for several spaces with $G = C_2$ and $G=C_4$.
format Preprint
id arxiv_https___arxiv_org_abs_2410_13971
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A Guide to Equivariant Parametrized Cohomology
Beaudry, Agnès
Lewis, Chloe
May, Clover
Pauli, Sabrina
Tatum, Elizabeth
Algebraic Topology
55N25
This article investigates equivariant parametrized cellular cohomology, a cohomology theory introduced by Costenoble-Waner for spaces with an action by a compact Lie group $G$. The theory extends the $RO(G)$-graded cohomology of a $G$-space $B$ to a cohomology graded by $RO(ΠB)$, the representations of the equivariant fundamental groupoid of $B$. This paper is meant to serve as a guide to this theory and contains some new computations. We explain the key ingredients for defining parametrized cellular cohomology when $G$ is a finite group, with particular attention to the case of the cyclic group $G=C_2$. We compute some examples and observe that $RO(ΠB)$ is not always free. When $G$ is the trivial group, we explain how to identify equivariant parametrized cellular cohomology with cellular cohomology in local coefficients. Finally, we illustrate the theory with some new computations of parametrized cellular cohomology for several spaces with $G = C_2$ and $G=C_4$.
title A Guide to Equivariant Parametrized Cohomology
topic Algebraic Topology
55N25
url https://arxiv.org/abs/2410.13971