English

Bredon sheaf cohomology

K-Theory and Homology 2026-04-10 v1 Algebraic Topology Operator Algebras

Abstract

For a finite group GG, we compute the algebraic KK-theory of the category of equivariant sheaves on a locally compact Hausdorff GG-space, generalizing a result of Efimov, and determine the equivariant EE-theory of the CC^*-algebra of continuous functions. These invariants admit natural descriptions in terms of a new equivariant cohomology theory, which we call Bredon sheaf cohomology. This theory recovers classical Bredon cohomology for GG-CW complexes and ordinary sheaf cohomology when GG is trivial. We establish its basic structural properties and prove a strong uniqueness theorem: any functor from the category of locally compact Hausdorff GG-spaces to a dualizable stable category satisfying equivariant open descent and cofiltered compact codescent is equivalent to Bredon sheaf cohomology, generalizing a result of Clausen.

Keywords

Cite

@article{arxiv.2604.08066,
  title  = {Bredon sheaf cohomology},
  author = {Guido Arnone and Devarshi Mukherjee and Thomas Nikolaus},
  journal= {arXiv preprint arXiv:2604.08066},
  year   = {2026}
}

Comments

39 pages

R2 v1 2026-07-01T12:00:54.966Z