We investigate an enrichment of the propositional modal language L with a "universal" modality ■ having semantics x ⊧ ■φ iff ∀y(y ⊧ φ), and a countable set of "names" - a special kind of propositional variables ranging over singleton sets of worlds. The obtained language ℒ $_{c}$ proves to have a great expressive power. It is equivalent with respect to modal definability to another enrichment ℒ(⍯) of ℒ, where ⍯ is an additional modality with the semantics x ⊧ ⍯φ (...) iff Vy(y ≠ x → y ⊧ φ). Model-theoretic characterizations of modal definability in these languages are obtained. Further we consider deductive systems in ℒ $_{c}$ . Strong completeness of the normal ℒ $_{c}$ logics is proved with respect to models in which all worlds are named. Every ℒ $_{c}$ -logic axiomatized by formulae containing only names (but not propositional variables) is proved to be strongly frame-complete. Problems concerning transfer of properties ([in]completeness, filtration, finite model property etc.) from ℒ to ℒ $_{c}$ are discussed. Finally, further perspectives for names in multimodal environment are briefly sketched. (shrink)

This much-needed book provides a thorough account of temporal logic, one of the most important areas of logic in computer science today. The book begins with a solid introduction to semantical and axiomatic approaches to temporal logic. It goes on to cover predicate temporal logic, meta-languages, general theories of axiomatization, many dimensional systems, propositional quantifiers, expressive power, Henkin dimension, temporalization of other logics, and decidability results. With its inclusion of cutting-edge results and unifying methodologies, this book is an indispensable reference (...) for both the pure logician and the theoretical computer scientist. (shrink)

ABSTRACT Real-time graphical interval logic is a modal logic for reasoning about time in which the basic modality is the interval. The logic differs from other logics in that it has a natural intuitive graphical representation that resembles the timing diagrams drawn by system designers. We have developed an automted deduction system for the logic, which includes a theorem prover and a user interface. The theorem prover checks the validity of proofs in the logic and produces counterexamples to invalid proofs. (...) The user interface includes a graphical editor that enables the user to create graphical formulas on a workstation display, and a database and proof manager that tracks proof dependencies and allows graphical formulas to be stored and retrieved. In this paper we describe the logic, the automated deduction system, and an application to robotics. (shrink)

Conjecture (1) of [Ma83] is confirmed here by the following result: if $3 \leq \alpha < \omega$, then there is a finite relation algebra of dimension α, which is not a relation algebra of dimension α + 1. A logical consequence of this theorem is that for every finite α ≥ 3 there is a formula of the form $S \subseteq T$ (asserting that one binary relation is included in another), which is provable with α + 1 variables, but not (...) provable with only α variables (using a special sequent calculus designed for deducing properties of binary relations). (shrink)

Temporal logic is gaining recognition as an attractive and versatile formalism for rigorously specifying and reasoning about computer programs, digital circuits and message-passing systems. This book introduces Tempura, a programming language based on temporal logic, Tempura provides a way of directly executing suitable temporal logic specifications of digital circuits, parallel programs and other dynamic systems. Since every Tempura statement is also a temporal formula, the entire temporal logic formalism can be used as the assertion language and semantics. One result is (...) that Tempura has the two seemingly contradictory properties of being a logic programming language and having imperative constructs such as assignment statements. The presentation investigates Interval Temporal Logic, a formalism with conventional temporal operators such as next and always as well as lesser known ones such as chop. This provides the basis for Tempura. The design of an interpreter for Tempura is also included, as are a variety of sample Tempura programs illustrating how to model both hardware and software. (shrink)

This investigation concerns representations of time by means of intervals, stemming from work of Allen and van Benthem . Allen described an Interval Calculus of thirteen binary relations on convex intervals over a linear order . He gave a practical algorithm for checking the consistency of a sublclass of Boolean constraints. ;First, we describe a completeness theorem for Allen's calculus, in its corresponding formulation as a first-order theory LM. LM is countably categorical, and axiomatises the complete theory of intervals over (...) a dense unbounded linear order. Its only countable model up to isomorphism is the non-trivial intervals over the rational numbers. ;Algorithms are given for quantifer-elimination, consistency checking, and satisfaction of arbitrary first-order formulas in the Interval Calculus. ;A natural countable model of the calculus is presented, the TUS, in which clock- and calendar-time may be represented in a straightforward way. ;Allen and Hayes described a first-order theory of intervals in . It is shown that the models of the theory are precisely the interval structures over an arbitrary unbounded linear order. ;An extension of the calculus to intervals which are union-of-convex is considered, introduced by concerns over the represention of interruptible processes. A taxonomy of necessary relations between union-of-convex intervals is given, and it is considered how to generalise to arbitrary non-convex intervals. Use of the extension is illustrated with an example of synthesising concurrent processes from high-level specifications. ;The extended calculus may be implemented in a high-level system with logic programming and data-types of sequence and set, and this feature is illustrated with a partial implementation of the TUS in such a system. (shrink)

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 ...