This book is the proceedings of the Structures in Concurrency Theory workshop (STRICT) that was held from 11 th to l3th May 1995 in Berlin, Germany. It includes three invited contributions - by J. de Bakker, E. Best et aI, and E. R. Olderog and M. Schenke - and all papers which were submitted and accepted for presentation. Concurrency Theory deals with formal aspects of concurrent systems. It uses partly competing and partly complementary formalisms and structures. The aim of this workshop was to present and compare different formalisms and results in Concurrency Theory. STRICT was organized by the Humboldt-University Berlin and the ESPRIT Basic Research Working Group CALIBAN. Original papers had been sought from all scientists in the field of Concurrency Theory. The Programme Committee selected twenty contributions with various different topics, including Petri Nets, Process Algebras, Distributed Algorithms, Formal Semantics, and others. I am grateful to the Programme Committee and to the other referees for the careful evaluation of the submitted papers.

This book presents the fundamentals of concurrency theory with clarity and rigor. The authors start with the semantic structure, namely labelled transition systems, which provides us with the means and the tools to express processes, to compose them, and to prove properties they enjoy. The rest of the book relies on Milner's Calculus of Communicating Systems, tailored versions of which are used to study various notions of equality between systems, and to investigate in detail the expressive power of the models considered. The authors proceed from very basic results to increasingly complex issues, with many examples and exercises that help to reveal the many subtleties of the topic. The book is suitable for advanced undergraduate and graduate students in computer science and engineering, and scientists engaged with theories of concurrency.

Intheworldweliveinconcurrencyisthenorm.Forexample,thehumanbody isamassivelyconcurrentsystem,comprisingahugenumberofcells,allsim- taneously evolving and independently engaging in their individual biological processing.Inaddition,inthebiologicalworld,trulysequentialsystemsrarely arise. However, they are more common when manmade artefacts are cons- ered. In particular, computer systems are often developed from a sequential perspective. Why is this? The simple reason is that it is easier for us to think about sequential, rather than concurrent, systems. Thus, we use sequentiality as a device to simplify the design process. However, the need for increasingly powerful, ?exible and usable computer systems mitigates against simplifying sequentiality assumptions. A good - ample of this is the all-powerful position held by the Internet, which is highly concurrent at many di?erent levels of decomposition. Thus, the modern c- puter scientist (and indeed the modern scientist in general) is forced to think aboutconcurrentsystemsandthesubtleandintricatebehaviourthatemerges from the interaction of simultaneously evolving components. Over a period of 25 years, or so, the ?eld of concurrency theory has been involved in the development of a set of mathematical techniques that can help system developers to think about and build concurrent systems. These theories are the subject matter of this book.

This book constitutes the thoroughly refereed proceedings of the 23rd International Conference on Concurrency Theory, CONCUR 2012, held in Newcastle upon Tyne, UK, September 4-7, 2012. The 35 revised full papers presented together with 4 invited talks were carefully reviewed and selected from 97 submissions. The papers are organized in topics such as reachability analysis; qualitative and timed systems; behavioural equivalences; temporal logics; session types; abstraction; mobility and space in process algebras; stochastic systems; probabilistic systems; Petri nets and non-sequential semantics; verification; decidability.

This book constitutes the refereed proceedings of the 9th International Conference on Concurrency Theory, CONCUR'98, held in Nice, France, in September 1998. The 35 revised full papers presented were carefully selected from a total of 104 submissions. Also presented are five invited contributions. Among the topics covered are moduls of computation and semantic domains, process algebras, Petri Nets, event structures, real-time systems, hybrid systems, model checking, verification techniques, refinement, rewriting, typing systems and algorithms, etc..

This book constitutes the refereed proceedings of the 8th International Conference on Concurrency Theory, CONCUR'97. held in Warsaw, Poland, in July 1997. The 24 revised full papers presented were selected by the program committee for inclusion in the volume from a total of 41 high-quality submissions. The volume covers all current topics in the science of concurrency theory and its applications, such as reactive systems, hybrid systems, model checking, partial orders, state charts, program logic calculi, infinite state systems, verification, and others.

This book constitutes the refereed proceedings of the 17th International Conference on Concurrency Theory, CONCUR 2006, held in Bonn, Germany in August 2006. The 29 revised full papers presented together with 5 invited papers were carefully reviewed and selected from 101 submissions. The papers are organized in topical sections on model checking, process calculi, minimization and equivalence checking, types, semantics, probability, bisimulation and simulation, real time, and formal languages.