On the quantization of conjugacy classes

Let G be a compact, simple, simply connected Lie group. A theorem of Freed-Hopkins-Teleman identifies the level k fusion ring R_k(G) of G with the twisted equivariant K-homology at level k+h, where h is the dual Coxeter number. In this paper, we review this result using the language of Dixmier-Douady bundles. We show that the additive generators of the group R_k(G) are obtained as K-homology push-forwards of the fundamental classes of conjugacy classes in G.