文摘
Kasparov (1988) defined a distinguished KK-homology fundamental class, so called the Dirac element. We prove a localization formula for the Dirac element in KK-homology of crossed product of C∗C∗-algebras. Then we define the quantization of Hamiltonian GG-spaces as a push-forward of the Dirac element. With this, we develop a KK-homological approach to the quantization commutes with reduction theorem.