This monograph provides a modern introduction to the theory of quantales.

First coined by C.J. Mulvey in 1986, quantales have since developed into a significant topic at the crossroads of algebra and logic, of notable interest to theoretical computer science. This book recasts the subject within the powerful framework of categorical algebra, showcasing its versatility through applications to C*- and MV-algebras, fuzzy sets and automata. With exercises and historical remarks at the end of each chapter, this self-contained book provides readers with a valuable source of references and hints for future research.

This book will appeal to researchers across mathematics and computer science with an interest in category theory, lattice theory, and many-valued logic.

Autorentext
Patrik Eklund develops applications based on many-valued representation of information. Information typically resides in the form of expressions and terms as integrated in knowledge structures, so that term functors, extendable to monads, become important instrumentations in applications. Categorical term constructions with applications to Goguen's category have been recently achieved (cf. Fuzzy Sets and Syst. 298, 128-157 (2016)). Information representation supported by such monads, and as constructed over monoidal closed categories, inherits many-valuedness in suitable ways also in implementations.

Javier Gutierrez Garcia has been interested in many-valued structures since the late 1990s. Over recent years these investigations have led him to a deeper understanding of the theory of quantales as the basis for a coherent development of many-valued structures (cf. Fuzzy Sets and Syst. 313 43-60 (2017)).

Since the late 1980s the research work of Ulrich Höhle has been motivated by a non-idempotent extension of topos theory.  A result of these activities is a non-commutative and non-idempotent theory of quantale sets which can be expressed as enriched category theory in a specific quantaloid (cf. Fuzzy Sets and Syst. 166, 1-43 (2011), Theory Appl. Categ. 25(13), 342-367 (2011)). These investigations have also led to a deeper understanding of the theory of quantales. Based on a new concept of prime elements, a characterization of semi-unital and spatial quantales by six-valued topological spaces has been achieved (cf. Order 32(3), 329-346 (2015)). This result has non-trivial applications to the general theory of C*-algebras.

Since the beginning of the 1990s the research work of Jari Kortelainen has been directed towards preorders and topologies as mathematical bases of imprecise information representation. This approach leads to the use of category theory as a suitable metalanguage. Especially, in cooperation with Patrik Eklund, his studies focus on categorical term constructions over specific categories (cf. Fuzzy Sets and Syst. 256, 211-235 (2014)) leading to term constructions over cocomplete monoidal biclosed categories (cf. Fuzzy Sets and Syst. 298, 128-157 (2016)).

Inhalt
Introduction.- 1 Foundations.- 2 Fundamentals of Quantales.- 3 Module Theory in Sup.- Appendix.- References.- Index.