Abstract
In this paper, we shall be concerned with a special kind of equicontinuous semi-topological semigroups of self-mappings on a weakly compact convex subset of a separated locally convex space, namely, the generalized non-expansive mappings and we shall introduce some common fixed point results for this kind of semigroups. Also, we study a characterization of the existence of a left invariant mean on almost and weakly almost periodic functions on separable semi-topological semigroups. Our results extend the results due to Lau and Zhang [17] and Lau [13].