U. Bunke

collaborators

5 papers

math.KT2025

Additive C*-categories and K-theory

Ulrich Bunke, Alexander Engel

We review the notions of a multiplier category and the $W^{*}$ -envelope of a $C^{*}$ -category. We then consider the notion of an orthogonal sum of a (possibly infinite) family of o…

math.AT2025

Paschke duality and assembly maps

Ulrich Bunke, Alexander Engel, Markus Land

We construct a natural transformation between two versions of $G$ -equivariant $K$ -homology with coefficients in a $G$ - $C^{*}$ -category for a countable discrete group $G$ . Its domai…

math.OA2025

A stable $\infty$ -category for equivariant $K K$ -theory

Ulrich Bunke, Alexander Engel, Markus Land

For a countable group $G$ we construct a small, idempotent complete, symmetric monoidal, stable $\infty$ -category $KK_{sep}^{G}$ whose homotopy category recovers…

math.AT2025

Breaking symmetries for equivariant coarse homology theories

Ulrich Bunke, Matthias Ludewig

We describe a symmetry breaking construction in coarse geometry which allows to obtain information about equivariant coarse homology classes by restriction to smaller groups and sp…

math.KT2025

$E$ -theory is compactly assembled

Ulrich Bunke, Benjamin Duenzinger

We show that the equivariant $E$ -theory category $E_{sep}^{G}$ for separable $C^{*}$ -algebras is a compactly assembled stable $\infty$ -category. We derive this re…