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.