Restriction to finite-index subgroups as étale extensions in topology, KK-theory and geometry

Abstract

For equivariant stable homotopy theory, equivariant KK-theory and equivariant derived categories, we show how restriction to a subgroup of finite index yields a finite commutative separable extension, analogous to finite étale extensions in algebraic geometry.

Title changed, final version, no significant changes, 17 pages

References in corpus (2)

• Stacks of group representations
• Separable extensions in tensor-triangular geometry and generalized Quillen stratification