Thickness in topological transformation semigroups
Tyler Haynes · International Journal of Mathematics and Mathematical Sciences · 1993
This article deals with thickness in topological transformation semigroups (x-semigroups).Thickness is used to establish conditions guaranteeing an invariant mean on a function space defined on a x-semigroup if there exists an invariant mean on its functions restricted to a sub-x-semigroup of the original x-semigroup.We sketch earlier results, then give many equivalent conditions for thickness on :-semigroups, and finally present theorems giving conditions tbr an invariant mean to exist on a function space.