Module Amenability for Semigroup Algebras
نویسندگان
چکیده
We extend the concept of amenability of a Banach algebra A to the case that there is an extra A -module structure on A, and show that when S is an inverse semigroup with subsemigroup E of idempotents, then A = l(S) as a Banach module over A= l(E) is module amenable iff S is amenable. When S is a discrete group, l(E) = C and this is just the celebrated Johnson’s theorem.
منابع مشابه
2n-Weak module amenability of semigroup algebras
Let $S$ be an inverse semigroup with the set of idempotents $E$. We prove that the semigroup algebra $ell^{1}(S)$ is always $2n$-weakly module amenable as an $ell^{1}(E)$-module, for any $nin mathbb{N}$, where $E$ acts on $S$ trivially from the left and by multiplication from the right. Our proof is based on a common fixed point property for semigroups.
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