Showing papers on "Topological semigroup published in 1985"

Abelian semigroups whose Stone-Čech compactifications have left ideal decompositions

Abstract: Stone-Cech compactifications of semigroups have aroused a good deal of interest recently. Several authors, for example Milnes [6], Marcri [5] and Baker and Butcher [1], have concentrated on problems of the existence of continuous extensions to βS of the operation in a topological semigroup S. For a discrete semigroup a separately continuous extension always exists, and others such as Pym and Vasudeva[8] have studied the compactifications of particular classes of semigroups. Further interest has centred on the algebraic structure of these compactifications; see for example Hindman[3].

The cardinality of the set of invariant means on a locally compact topological semigroup

Abstract: For a large class of locally compact topological semigroups, which include all non-compact, a-compact and locally compact topological groups as a very special case, we show that the cardinality of the set of all invariant means on the space of weakly uniformly continuous functions is either 0 or > 2’; where c denotes the cardinality of continuum. Compositio Mathematica 54 (1985) 41-49. O 1985 Martinus Nijhoff Publishers, Dordrecht. Printed in The Netherlands.

Constructions of positive commutative semigroups on the plane, II

Abstract: A positive semiroup is a topological semigroup containinq a subseminroup N isomorphic to the multiplicative semigroup of nonnegative real numbers, embedded as