2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/106222Let $M(S)$ be the Banach algebra of all bounded regular Borel measures on a locally compact Hausdorff semitopological semigroup $S$ with variation norm and convolution as multiplication. We obtain necessary and sufficient conditions for $M(S)^{*}$ to have a topologically left invariant mean.7 pagesGroup Theory22A20; 43A60text