Cyclic homology of cleft extensions of algebras

Abstract

Let [Formula: see text] be a commutative algebra with [Formula: see text] and let [Formula: see text] be a cleft extension of [Formula: see text]. We obtain a new mixed complex, simpler than the canonical one, giving the Hochschild and cyclic homologies of [Formula: see text] relative to [Formula: see text]. This complex resembles the canonical reduced mixed complex of an augmented algebra. We begin the study of our complex showing that it has a harmonic decomposition like the one considered by Cuntz and Quillen for the normalized mixed complex of an algebra.