Cyclic Cohomology of Corings

摘要

We define cyclic cohomology of corings over not necessarily commutative algebras. Our method is a generalization of Hopf-cyclic cohomology obtained by replacing coalgebras and Hopf algebras with corings and para-Hopf algebroids, respectively. We also study the dual of this theory whose cyclic cohomology, in contrast with the case of algebras and coalgebras, is not trivial.