On pseudo-amenability of commutative semigroup algebras and their second duals

摘要

In this paper, we first characterize pseudo-amenability of semigroup algebras for a certain class of commutative semigroups S, the so-called archimedean semigroups. We show that for an archimedean semigroup S, pseudo-amenability, amenability and approximate amenability of are equivalent. Then for a commutative semigroup S, we show that pseudo-amenability of implies that S is a Clifford semigroup. Finally, we give some results on pseudo-amenability and approximate amenability of the second dual of a certain class of commutative semigroup algebras (S).