Bonn Topology Group - Abstracts
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Talk
October 20, 2026
Miguel Barrero (MPIM Bonn): Proper equivariant spectra and a separability property for infinite discrete groups
Abstract
Let G be an infinite discrete group. Proper equivariant G-spectra are defined as a limit of genuine H-spectra as H ranges over the finite subgroups of G. In joint work with Tobias Barthel, Drew Heard, and Irakli Patchkoria, we study the Balmer spectrum of the category of dualizable proper G-spectra. We introduce a new separability property for infinite groups, and in the first part of this talk I will discuss how this property guarantees that said Balmer spectrum is given by a colimit of the Balmer spectra for the finite subgroups of G. I will then present some examples of groups with and without this separability property, and relate it to other commonly studied properties of groups. I will also discuss how the subcategory of dualizable proper G-spectra is larger than what one would originally expect.
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