The Action of a Left Amenable Semi-topological Semigroup on a Weakly Compact Subset of a Banach Space with Normal Structure

摘要

Let S be left amenable semi-topological semigroup such that its weak almost periodic compactification Sw is a topological semigroup. We show that every separately continuous, non-expansive and equicontinuous action of S on a weakly compact convex subset of a Banach space with normal structure has a fixed point.