Restriction to Finite-index Subgroups as Étale Extensions in Topology, Kk-theory and Geometry
نویسندگان
چکیده
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.
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