First and Second Module Cohomology Groups for Non Commutative Semigroup Algebras

Abstract

‎Let $S$ be a (not necessarily commutative) Clifford semigroup with idempotent set $E$. In this paper, we show that the first (second) Hochschild cohomology group and the first (second) module cohomology group of semigroup algbera $\ell^1(S)$ with coefficients in $\ell^\infty(S)$ (and also $\ell^1(S)^{(2n-1)}$ for $n\in \mathbb{N}$) are equal.

Keywords

• clifford semigroup
• weak amenability
• weak module amenability
• cohomology group
• module cohomology group