This is the latest in a series of proceedings of conferences on the Mathematical Foundations of Programming Semantics. The purpose of the series is to bring together mathematicians and theoretical computer scientists who share the common interests of working on problems related to programming language semantics. The purpose of the book is to bring into print as quickly as possible papers which reflect the state of research on the topics comprising this area. The intended audience for the book consists of those researchers and graduate students with an interest in the research areas which are related to those presented in the book: programming language semantics, including algebraic, denotational and operational semantics, logics of programs, specification techniques, etc., and the relevant areas of mathematics research, including category theory, domain theory, ordered structures and lattice theory, and metric space methods. The papers included in the book represent the latest results in various facets of this rather broad research area, and this is the first time some of the ideas contained in these works are appearing in print.

This volume contains survey papers by the invited speakers at the Conference on Semigroup Theory and Its Applications which took place at Tulane University in April, 1994. The authors represent the leading areas of research in semigroup theory and its applications, both to other areas of mathematics and to areas outside mathematics. Included are papers by Gordon Preston surveying Clifford's work on Clifford semigroups and by John Rhodes tracing the influence of Clifford's work on current semigroup theory. Notable among the areas of application are the paper by Jean-Eric Pin on applications of other areas of mathematics to semigroup theory and the paper by the editors on an application of semigroup theory to theoretical computer science and mathematical logic. All workers in semigroup theory should find this volume invaluable.