Hopf-type Cyclic Cohomology via Karoubi Operator

Abstract

In this paper we propose still another approach to the Hopf-type cyclic homology of Hopf algebras, introduced by A. Connes and H. Moscovici. Our construction is based on the notion of "universal differential calculus" on an algebra. Few remarks, concerning the possible generalizations and applications of this approach are made. (This is only a preliminary version of the paper. Only outlines of some ideas are given.)