Hypergroup algebras as topological algebras

Abstract

Let K be a locally compact hypergroup endowed with a left Haar measure and let L1(K) be the usual Lebesgue space of K with respect to the left Haar measure. We investigate some properties of L1(K) under a locally convex topology β1. Among other things, the semireflexivity of (L1(K),β1) and of sequentiallyβ1-continuous functionals is studied. We also show that (L1(K),β1) with the convolution multiplication is always a complete semitopological algebra, whereas it is a topological algebra if and only if K is compact.