A KK-theoretic perspective of quantization commutes with reduction

Abstract: We reframe Paradan-Vergne's approach to quantization commutes with reduction in KK-theory through a recent formalism introduced by Kasparov, focusing more especially the index theoretic parts that lead to their "Witten non-abelian localization formula". While our method uses the same ingredients as their's in spirit, interesting conceptual simplifications occur, and the relationship to the Ma-Tian-Zhang analytic approach becomes quite transparent.