Clausal Resolution for Modal Logics of Confluence

We present a clausal resolution-based method for normal multimodal logics of confluence, whose Kripke semantics are based on frames characterised by appropriate instances of the Church-Rosser property. Here we restrict attention to eight families of such logics. We show how the inference rules related to the normal logics of confluence can be systematically obtained from the parametrised axioms that characterise such systems. We discuss soundness, completeness, and termination of the method. In particular, completeness can be modularly proved by showing that the conclusions of each newly added inference rule ensures that the corresponding conditions on frames hold. Some examples are given in order to illustrate the use of the method.Comment: 15 pages, 1 figure. Preprint of the paper accepted to IJCAR 201

Towards Resolution-based Reasoning for Connected Logics

AbstractThe method of connecting logics has gained a lot of attention in the knowledge representation and ontology communities because of its intuitive semantics and natural support for modular KR, its generality, and its robustness concerning decidability preservation. However, so far no dedicated automated reasoning solutions have been developed, and the only reasoning available was via translation into sufficiently expressive logics. In this paper, we present a simple modalised version of basic E-connections, and develop a sound, complete, and terminating resolution-based reasoning procedure. The approach is modular and can be extended to more expressive versions of E-connections

A Resolution Prover for Coalition Logic

We present a prototype tool for automated reasoning for Coalition Logic, a non-normal modal logic that can be used for reasoning about cooperative agency. The theorem prover CLProver is based on recent work on a resolution-based calculus for Coalition Logic that operates on coalition problems, a normal form for Coalition Logic. We provide an overview of coalition problems and of the resolution-based calculus for Coalition Logic. We then give details of the implementation of CLProver and present the results for a comparison with an existing tableau-based solver

Logica condicional forte

Orientador: Jacques WainerDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: As lógicas não-monotônicas podem ser classificadas, segundo as conclusões que podem ser obtidas, em fracas ou fortes. As lógicas fortes, entre as quais se incluem sistemas nãomonotônicos clássicos [Reiter, 80] [McCarthy,80] [Moore, 85] [Marek e Truszczynski, 91], permitem conclusões não desejáveis, deixando de tratar aspectos como, por exemplo, especificidade. Lógicas não-monotônicas fracas, como as condicionais [Delgrande, 87] [Boutilier, 94], não permitem algumas conclusões desejáveis, como as que tratam de irrelevância e herança de propriedades, por exemplo. Esta tese apresenta a semântica da Lógica Condicional Forte (LCF), que atende às características gerais da relação de conseqüência não-monotônica preferencial [Kraus et aI, 90], suportadas pelas lógicas condicionais, mas que, além disso, também lida com outros modos de raciocínio (irrelevância, herança e ambigüidade) não tratados por tais lógicas. A definição da semântica do condicional é mais resttitiva e, além disso, diferentemente de enfoques recentes, que procuram fortalecer lógicas já existentes através de filtros sobre o conjunto de modelos, é proposto um método para a construção dos modelos a partir de. informação local (obtida dos condicionais individualmente) e global (obtida dos condicionais conjuntamente) extraídas diretamente da base de conhecimentoAbstract: Not informedMestradoMestre em Ciência da Computaçã

Anti-prenexing and prenexing for modal logics (extended version). Available at http://www.cic.unb.br/∼nalon and http://www.csc.liv.ac.uk/∼clare/cld-pubs

Abstract. Efficient proof methods for proving properties specified by means of normal modal logics are highly desirable, as such logical systems have been widely used in computer science to represent complex situations. Resolution-based methods are often designed to deal with formulae in a normal form and the efficiency of the method (also) relies on how efficient (in the sense of producing fewer and/or shorter clauses) the translation procedure is. We present a normal form for normal modal logics and show how the use of simplification, for specific normal logics, together with anti-prenexing and prenexing techniques help us to produce better sets of clauses.

A Resolution-Based Theorem Prover for Kn{\textsf {K}}_{n}^{}Kn: Architecture, Refinements, Strategies and Experiments

In this paper we describe the implementation of KSP, a resolution-based prover for the basic multimodal logic Kn. The prover implements a resolution-based calculus for both local and global reasoning. The user can choose different normal forms, refinements of the basic resolution calculus, and strategies. We describe these options in detail and discuss their implications. We provide experiments comparing some of these options and comparing the prover with other provers for this logic

Tableaux for Temporal Logics of Knowledge: Synchronous Systems of Perfect Recall Or No Learning

The paper describes tableaux based proof methods for temporal logics of knowledge allowing interaction axioms between the modal and temporal components. Such logics can be used to specify systems that involve the knowledge of processes or agents and which change over time, for example agent based systems or knowledge games. The interaction axioms allow the description of how knowledge evolves over time and makes reasoning in such logics theoretically more complex. Completeness arguments for the tableaux are discussed