English

A Complete Formulation of Baum-Conens' Conjecture for the Action of Discrete Quantum Groups

K-Theory and Homology 2007-05-23 v1 Operator Algebras

Abstract

We formulate a version of Baum-Connes' conjecture for a discrete quantum group, building on our earlier work (\cite{GK}). Given such a quantum group \cla\cla, we construct a directed family {\cleF}\{\cle_F \} of CC^*-algebras (FF varying over some suitable index set), borrowing the ideas of \cite{cuntz}, such that there is a natural action of \cla\cla on each \cleF\cle_F satisfying the assumptions of \cite{GK}, which makes it possible to define the "analytical assembly map", say μir,F\mu^{r,F}_i, i=0,1,i=0,1, as in \cite{GK}, from the \cla\cla-equivariant KK-homolgy groups of \cleF\cle_F to the KK-theory groups of the "reduced" dual \clar^\hat{\cla_r} (c.f. \cite{GK} and the references therein for more details). As a result, we can define the Baum-Connes' maps μir:limKKi\cla(\cleF,\IC)\raroKi(\clar^),\mu^r_i : \stackrel{\rm lim}{\longrightarrow} KK_i^\cla(\cle_F,\IC) \raro K_i(\hat{\cla_r}), and in the classical case, i.e. when \cla\cla is C0(G)C_0(G) for a discrete group, the isomorphism of the above maps for i=0,1i=0,1 is equivalent to the Baum-Connes' conjecture. Furthermore, we verify its truth for an arbitrary finite dimensional quantum group and obtain partial results for the dual of SUq(2).SU_q(2).

Cite

@article{arxiv.math/0310470,
  title  = {A Complete Formulation of Baum-Conens' Conjecture for the Action of Discrete Quantum Groups},
  author = {Debashish Goswami and A. O. Kuku},
  journal= {arXiv preprint arXiv:math/0310470},
  year   = {2007}
}

Comments

to appear in "K Theory" (special volume for H. Bass). A preliminary version was available as ICTP preprint since the early this year