Part III, Free Actions of Compact Quantum Groups on ${\rm C}^*$-Algebras

[摘要] We study and classify free actions of compact quantum groups on unital ${\rm C}^*$-algebras in terms of generalized factor systems. Moreover, we use these factor systems to show that all finite coverings of irrational rotation ${\rm C}^*$-algebras are cleft.

[关键词] free action;C∗ -algebra;quantum group;factor system;finite covering