%0 Journal Article
%T A New Characterisation of Idempotent States on Finite and Compact Quantum Groups
%A Uwe Franz
%A Adam Skalski
%J Mathematics
%D 2009
%I arXiv
%R 10.1016/j.crma.2009.06.015
%X We show that idempotent states on finite quantum groups correspond to pre-subgroups in the sense of Baaj, Blanchard, and Skandalis. It follows that the lattices formed by the idempotent states on a finite quantum group and by its coidalgebras are isomorphic. We show furthermore that these lattices are also isomorphic for compact quantum groups, if one restricts to expected coidalgebras.
%U http://arxiv.org/abs/0906.2362v1