Globalization of group cohomology in the sense of Alvares-Alves-Redondo

Abstract Recently E. R. Alvares, M. M. Alves and M. J. Redondo introduced a cohomology for a group G with values in a module over the partial group algebra K par ( G ) , which is different from the partial group cohomology defined earlier by the first two named authors of the present paper. Given a unital partial action α of G on a (unital) algebra A we consider A as a K par ( G ) -module in a natural way and study the globalization problem for the cohomology in the sense of Alvares-Alves-Redondo with values in A . The problem is reduced to an extendibility property of cocycles. Furthermore, assuming that A is a product of blocks, we prove that any cocycle is globalizable, and globalizations of cohomologous cocycles are also cohomologous. As a consequence we obtain that the Alvares-Alves-Redondo cohomology group H p a r n ( G , A ) is isomorphic to the usual cohomology group H n ( G , M ( B ) ) , where M ( B ) is the multiplier algebra of B and B is the algebra under the enveloping action of α.