Weak module amenability for the second dual of a Banach algebra

Abstract

In this paper we study the weak module amenability of Banach algebras which are Banach modules over another Banach algebra with compatible actions. We show that for every module derivation D : A ↦ ( A/J_A )^∗ if D^∗∗(A^∗∗) ⊆ WAP (A/J_A ), then weak module amenability of A^∗∗ implies that of A. Also we prove that under certain conditions for the module derivation D, if A^∗∗ is weak module amenable then A is also weak module amenable.