Involutions on the second duals of group algebras versus subamenable groups
Let L1(G)∗∗ be the second dual of the group algebra L(G) of a locally compact group G. We study the question of involutions on L1(G)∗∗. A new class of subamenable groups is introduced which is universal for all groups. There is no involution on L1(G)∗∗ for a subamenable group G.