Modal Logic is a branch of logic with applications in many related disciplines such as computer science, philosophy, linguistics and artificial intelligence. Over the last twenty years, in all of these neighbouring fields, modal systems have been developed that we call multi-dimensional. (Our definition of multi-dimensionality in modal logic is a technical one: we call a modal formalism multi-dimensional if, in its intended semantics, the universe of a model consists of states that are tuples over some more basic set.) This book treats such multi-dimensional modal logics in a uniform way, linking their mathematical theory to the research tradition in algebraic logic. We will define and discuss a number of systems in detail, focusing on such aspects as expressiveness, definability, axiomatics, decidability and interpolation. Although the book will be mathematical in spirit, we take care to give motivations from the disciplines mentioned earlier on.

Finite model theory,as understoodhere, is an areaof mathematicallogic that has developed in close connection with applications to computer science, in particular the theory of computational complexity and database theory. One of the fundamental insights of mathematical logic is that our understanding of mathematical phenomena is enriched by elevating the languages we use to describe mathematical structures to objects of explicit study. If mathematics is the science of patterns, then the media through which we discern patterns, as well as the structures in which we discern them, command our attention. It isthis aspect oflogicwhichis mostprominentin model theory,"thebranchof mathematical logic which deals with the relation between a formal language and its interpretations". No wonder, then, that mathematical logic, and ?nite model theory in particular, should ?nd manifold applications in computer science: from specifying programs to querying databases, computer science is rife with phenomena whose understanding requires close attention to the interaction between language and structure. This volume gives a broadoverviewof some central themes of ?nite model theory: expressive power, descriptive complexity, and zero-one laws, together with selected applications to database theory and arti?cial intelligence, es- cially constraint databases and constraint satisfaction problems. The ?nal chapter provides a concise modern introduction to modal logic,which emp- sizes the continuity in spirit and technique with ?nite model theory.

Modal Logic is a branch of logic with applications in many related disciplines such as computer science, philosophy, linguistics and artificial intelligence. Over the last twenty years, in all of these neighbouring fields, modal systems have been developed that we call multi-dimensional. (Our definition of multi-dimensionality in modal logic is a technical one: we call a modal formalism multi-dimensional if, in its intended semantics, the universe of a model consists of states that are tuples over some more basic set.) This book treats such multi-dimensional modal logics in a uniform way, linking their mathematical theory to the research tradition in algebraic logic. We will define and discuss a number of systems in detail, focusing on such aspects as expressiveness, definability, axiomatics, decidability and interpolation. Although the book will be mathematical in spirit, we take care to give motivations from the disciplines mentioned earlier on.

Advances in Modal Logic is a unique international forum for presenting the latest results and new directions of research in modal logic broadly conceived. The topics dealt with are of interdisciplinary interest and range from mathematical, computational, and philosophical problems to applications in knowledge representation and formal linguistics. This volume contains invited and contributed papers from the sixth conference in the series, held for the first time outside Europe, in Noosa, Queensland, Australia, in September 2006. It reports on considerable progress, both in the foundations of modal logic and in a number of application areas. It includes papers on the theory of modal logic itself, on process theory, multi-agent systems and spatial reasoning, and work on quantified modal logic, modal reasoning methods, and philosophical issues.

This modern, advanced textbook reviews modal logic, a field which caught the attention of computer scientists in the late 1970's. The development is mathematical; prior acquaintance with first-order logic and its semantics is assumed, and familiarity with the basic mathematical notions of set theory is required. The authors focus on the use of modal languages as tools to analyze the properties of relational structures, including their algorithmic and algebraic aspects. Applications to issues in logic and computer science such as completeness, computability and complexity are considered.

Finite model theory,as understoodhere, is an areaof mathematicallogic that has developed in close connection with applications to computer science, in particular the theory of computational complexity and database theory. One of the fundamental insights of mathematical logic is that our understanding of mathematical phenomena is enriched by elevating the languages we use to describe mathematical structures to objects of explicit study. If mathematics is the science of patterns, then the media through which we discern patterns, as well as the structures in which we discern them, command our attention. It isthis aspect oflogicwhichis mostprominentin model theory,"thebranchof mathematical logic which deals with the relation between a formal language and its interpretations". No wonder, then, that mathematical logic, and ?nite model theory in particular, should ?nd manifold applications in computer science: from specifying programs to querying databases, computer science is rife with phenomena whose understanding requires close attention to the interaction between language and structure. This volume gives a broadoverviewof some central themes of ?nite model theory: expressive power, descriptive complexity, and zero-one laws, together with selected applications to database theory and arti?cial intelligence, es- cially constraint databases and constraint satisfaction problems. The ?nal chapter provides a concise modern introduction to modal logic,which emp- sizes the continuity in spirit and technique with ?nite model theory.

Labelled transition systems are mathematical models for dynamic behaviour, or processes, and thus form a research field of common interest to logicians and theoretical computer scientists. In computer science, this notion is a fundamental one in the formal analysis of programming languages, in particular in process theory. In modal logic, transition systems are the central object of study under the name of Kripke models. This volume collects a number of research papers on modal logic and process theory. Its unifying theme is the notion of a bisimulation. Bisimulations are relations over transition systems, and provide a key tool in identifying the processes represented by these structures. The volume offers an up-to-date overview of perspectives on labelled transition systems and bisimulations.

Labelled transition systems are mathematical models for dynamic behaviour, or processes, and thus form a research field of common interest to logicians and theoretical computer scientists. In computer science, this notion is a fundamental one in the formal analysis of programming languages, in particular in process theory. In modal logic, transition systems are the central object of study under the name of Kripke models. This volume collects a number of research papers on modal logic and process theory. Its unifying theme is the notion of a bisimulation. Bisimulations are relations over transition systems, and provide a key tool in identifying the processes represented by these structures. The volume offers an up-to-date overview of perspectives on labelled transition systems and bisimulations.