Recent years have been blessed with an abundance of logical systems, arising from a multitude of applications. A logic can be characterised in many different ways. Traditionally, a logic is presented via the following three components: 1. an intuitive non-formal motivation, perhaps tie it in to some application area 2. a semantical interpretation 3. a proof theoretical formulation. There are several types of proof theoretical methodologies, Hilbert style, Gentzen style, goal directed style, labelled deductive system style, and so on. The tableau methodology, invented in the 1950s by Beth and Hintikka and later per fected by Smullyan and Fitting, is today one of the most popular, since it appears to bring together the proof-theoretical and the semantical approaches to the pre of a logical system and is also very intuitive. In many universities it is sentation the style first taught to students. Recently interest in tableaux has become more widespread and a community crystallised around the subject. An annual tableaux conference is being held and proceedings are published. The present volume is a Handbook a/Tableaux pre senting to the community a wide coverage of tableaux systems for a variety of logics. It is written by active members of the community and brings the reader up to frontline research. It will be of interest to any formal logician from any area.

This book constitutes the refereed proceedings of the 16th International Conference on Automated Reasoning with Analytic Tableaux and Related Methods, TABLEAUX 2007, held in Aix en Provence, France. It covers the wide range of logics, from intuitionistic and substructural logics to modal logics (including temporal and dynamic logics), from many-valued logics to nonmonotonic logics, and from classical first-order logic to description logics.

This book constitutes the refereed proceedings of the International Conference on Analytic Tableaux and Related Methods, TABLEAUX'99, held in Saratoga Springs, NY, USA, in June 1999. The volume presents 18 revised full papers and three system descriptions selected from 41 submissions. Also included are system comparisons and abstracts of an invited paper and of two tutorials. All current issues surrounding mechanization of reasoning with tableaux and similar methods are addressed - ranging from theoretical foundations to implementation and systems development and applications, as well as covering a broad variety of logic calculi. As application areas, formal verification of software and computer systems, deductive databases, knowledge representation, and systems diagnosis are covered.

th FM 2009, the 16 International Symposium on Formal Methods, marked the 10th an- versary of the First World Congress on Formal Methods that was held in 1999 in Toulouse, France. We wished to celebrate this by advertising and organizing FM 2009 as the Second World Congress in the FM series, aiming to once again bring together the formal methods communities from all over the world. The statistics displayed in the table on the next page include the number of countries represented by the Programme Committee members, as well as of the authors of submitted and accepted papers. Novel this year was a special track on tools and industrial applications. Subm- sions of papers on these topics were especially encouraged, but not given any special treatment. (It was just as hard to get a special track paper accepted as any other paper.) What we did promote, however, was a discussion of how originality, contri- tion, and soundness should be judged for these papers. The following questions were used by our Programme Committee.

This book constitutes the proceedings of the 12 International Conference on Relational and Algebraic Methods in Computer Science, RAMICS 2011, held in Rotterdam, The Netherlands, in May/June 2011. This conference merges the RelMICS (Relational Methods in Computer Science) and AKA (Applications of Kleene Algebra) conferences, which have been a main forum for researchers who use the calculus of relations and similar algebraic formalisms as methodological and conceptual tools. Relational and algebraic methods and software tools turn out to be useful for solving problems in social choice and game theory. For that reason this conference included a special track on Computational Social Choice and Social Software. The 18 papers included were carefully reviewed and selected from 27 submissions. In addition the volume contains 2 invited tutorials and 5 invited talks.

Handbook of Automated Reasoning.

Possible worlds models were introduced by Saul Kripke in the early 1960s. Basically, a possible world's model is nothing but a graph with labelled nodes and labelled edges. Such graphs provide semantics for various modal logics (alethic, temporal, epistemic and doxastic, dynamic, deontic, description logics) and also turned out useful for other nonclassical logics (intuitionistic, conditional, several paraconsistent and relevant logics). All these logics have been studied intensively in philosophical and mathematical logic and in computer science, and have been applied increasingly in domains such as program semantics, artificial intelligence, and more recently in the semantic web. Additionally, all these logics were also studied proof theoretically. The proof systems for modal logics come in various styles: Hilbert style, natural deduction, sequents, and resolution. However, it is fair to say that the most uniform and most successful such systems are tableaux systems. Given logic and a formula, they allow one to check whether there is a model in that logic. This basically amounts to trying to build a model for the formula by building a tree. This book follows a more general approach by trying to build a graph, the advantage being that a graph is closer to a Kripke model than a tree. It provides a step-by-step introduction to possible worlds semantics (and by that to modal and other nonclassical logics) via the tableaux method. It is accompanied by a piece of software called LoTREC (www.irit.fr/Lotrec). LoTREC allows to check whether a given formula is true at a given world of a given model and to check whether a given formula is satisfiable in a given logic. The latter can be done immediately if the tableau system for that logic has already been implemented in LoTREC. If this is not yet the case LoTREC offers the possibility to implement a tableau system in a relatively easy way via a simple, graph-based, interactive language.