We describe a method for reducing the complexity of temporal logic model checking in systems composed of many parallel processes. The goal is to check properties of the components of a system and then deduce global properties from these local properties. The main difficulty with this type of approach is that local properties are often not preserved at the global level. We present a general framework for using additional interface processes to model the environment for a component. These interface processes are typically much simpler than the full environment of the component. By composing a component with its interface processes and then checking properties of this composition, we can guarantee that these properties will be preserved at the global level. We give two example compositional systems based on the logic CTL*.

A computer program capable of acting intelligently in the world must have a general representation of the world in terms of which its inputs are interpreted. Designing such a program requires commitments about what knowledge

We present a foundational language for distributed programming, called Lambda 5, that addresses both mobilityof code and locality of resources. In order to construct our system, we appeal to the powerful propositions-as-types interpretation of logic. Specifically, we take the possible worlds of the intuitionistic modal logic IS5 to be nodes ona network, and the connectives 2 and 3 to reflect mobility and locality, respectively. We formulate a novel systemof natural deduction for IS5, decomposing the introduction and elimination rules for 2 and 3, thereby allowing thecorresponding programs to be more direct. We then give an operational semantics to our calculus that is type-safe, logically faithful, and computationally realistic.

The notion of time is ubiquitous in any activity that requires intelligence. In particular, several important notions like change, causality, action are described in terms of time. Therefore, the representation of time and reasoning about time is of crucial importance for many Artificial Intelligence systems. Specifically during the last 10 years, it has been attracting the attention of many AI researchers. In this survey, the results of this work are analysed. Firstly, Temporal Reasoning is defined. Then, the most important representational issues which determine a Temporal Reasoning approach are introduced: the logical form on which the approach is based, the ontology (the units taken as primitives, the temporal relations, the algorithms that have been developed,. . . ) and the concepts related with reasoning about action (the representation of change, causality, action,. . . ). For each issue the different choices in the literature are discussed. 1 Introduction The notion of time i...

. We define sequent-style calculi for nominal tense logics characterized by classes of modal frames that are first-order definable by certain \Pi 0 1 -formulae and \Pi 0 2 -formulae. The calculi are based on d'Agostino and Mondadori's calculus KE and therefore they admit a restricted cutrule that is not eliminable. A nice computational property of the restriction is, for instance, that at any stage of the proof, only a finite number of potential cut-formulae needs to be taken under consideration. Although restrictions on the proof search (preserving completeness) are given in the paper and most of them are theoretically appealing, the use of those calculi for mechanization is however doubtful. Indeed, we present sequent calculi for fragments of classical logic that are syntactic variants of the sequent calculi for the nominal tense logics. 1 Introduction Background. The nominal tense logics are extensions of Prior tense logics (see e.g. [Pri57, RU71]) by adding nomina...

In these notes we will review the automata-theoretic verification method and propositional linear temporal logic, with specific emphasis on their potential application to distributed software verification. An important

. In many existing process modelling approaches, the emphasis is on the representations of process models, but not so much on the development of them. In this paper we present a method, called OBM, for developing such representations using a stepwise refinement technique. An example is used to show how a model may be gradually refined. 1 Background and Introduction In EWSPT'92 [10], we reported a small case study [24] which we undertook to investigate the application of an existing concurrent formal specification method, Base Model (BM) [23], to process modelling. The case study showed that although BM could be used as a specification method for some applications, particularly those targeted by the process modelling language PML [5], there was still a wide scope for improvement so that BM could be a more suitable technique for process modelling. Our subsequent work mainly concentrated on specifying 1 the ISPW-6 software process problem example (ISPW-6 example for short) [15]. As a ...

We positively answer the old question whether temporal logic with past is more succinct than pure-future temporal logic. Surprisingly, the proof is quite simple and elementary, although the question has been open for twenty years.

A spatial logic is a modal logic of which the models are the mathematical models of space. Successively considering the mathematical models of space that are the incidence geometry and the projective geometry, we will successively establish the language, the semantical basis, the axiomatical presentation, the proof of the decidability and the proof of the completeness of INC, the modal multilogic of incidence geometry, and PRO, the modal multilogic of projective geometry. 1 Introduction Our perception of space is less direct than our perception of time which is not the result of thought but the outcome of consciousness. Nevertheless, we should acknowledge that space more vigorously asserts its truth to our senses than time : we can see the objects that occupy space whereas we cannot know similarly the ways of the events that fill time [12]. Well then, why, since the works of Dummett and Lemmon [8], Hintikka [14] and Prior [22] on the logic of the Diodorean modalities, has temporal lo...

In their framework for ontological analysis, Guarino and Welty provide a number of insights that are useful for guiding the design of taxonomic hierarchies. However, the formal statements of these insights as logical schemata are flawed in a number of ways, including inconsistent notation that makes the intended semantics of the logic unclear, false claims of logical consequence, and definitions that provably result in the triviality of some of their property features. This paper makes a negative contribution, by demonstrating these flaws in a rigorous way, but also makes a positive contribution wherever possible, by identifying the underlying intuitions that the faulty definitions were intended to capture, and attempting to formalize those intuitions in a more accurate way. Categories & Descriptors: I.2.4 [Knowledge Representation Formalisms and Methods]: Predicate logic Keywords: ontology, taxonomy 1.