Noncommutative Differential Calculus Structure on Secondary Hochschild (co)homology

TL;DR

This paper explores the structure of secondary Hochschild (co)homology for $B$-algebras, establishing a noncommutative differential calculus framework connecting different (co)homology theories.

Contribution

It introduces a connection between two secondary Hochschild (co)homology theories and demonstrates they form a noncommutative differential calculus.

Findings

Established a link between two secondary Hochschild (co)homology theories.

Proved the pair forms a noncommutative differential calculus.

Extended classical Hochschild theory to the secondary case.

Abstract

Let $B$ be a commutative algebra and $A$ be a $B$-algebra (determined by an algebra homomorphism $\varepsilon:B\rightarrow A$). M. D. Staic introduced a Hochschild like cohomology $H^{\bullet}((A,B,\varepsilon);A)$ called secondary Hochschild cohomology, to describe the non-trivial $B$-algebra deformations of $A$. J. Laubacher et al later obtained a natural construction of a new chain (and cochain) complex $\overline{C}_{\bullet}(A,B,\varepsilon)$ (resp. $\overline{C}^{\bullet}(A,B,\varepsilon)$) in the process of introducing the secondary cyclic (co)homology. It turns out that unlike the classical case of associative algebras (over a field), there exist different (co)chain complexes for the $B$-algebra $A$. In this paper, we establish a connection between the two (co)homology theories for $B$-algebra $A$. We show that the pair $\big(H^{\bullet}((A,B,\varepsilon);A),HH_{\bullet}(A,B,\varepsilon)\big)$ forms a non-commutative differential calculus, where $HH_{\bullet}(A,B,\varepsilon)$ denotes the homology of the complex $\overline{C}_{\bullet}(A,B,\varepsilon)$.