In this paper we present a modal extension of logic programming which provides reasoning capabilities in a multiagent situation The language con tains embedded implications modal operators ai to represent agent beliefs together with a kind of common knowledge operator In this language we can also de ne modules compose them in several ways and also we can perform hypothetical reasoning

We propose a model-checking tool for on-the-fly verification of properties expressed in a branching-time temporal logic based on a deontic interpretation of classical modal and temporal operators over modal transition systems. We apply this tool to the analysis of variability in behavioural descriptions of families of services.

The aim of this paper is to construct a tableau decision algorithm for the modal description logic KALC with constant domains. More precisely , we present a tableau procedure that is capable of deciding, given an ALC-formula ' with extra modal operators (which are applied only to concepts and TBox axioms, but not to roles), whether ' is satiss-able in a model with constant domains and arbitrary...

We say that things happen accidentally when they do indeed happen, but only by chance. In the opposite situation, an essential happening is inescapable, its inevitability being the sine qua non for its very occurrence. This paper will investigate modal logics on a language tailored to talk about essential and accidental statements. Completeness of some among the weakest and the strongest such s...

This paper starts from the elementary observation that what is usually called a predicate lifting in coalgebraic modal logic is in fact an endomap of indexed categories. This leads to a systematic review of basic results in predicate logic for functors and monads, involving induction and coinduction principles for functors and compositional modal operators for monads.

We provide a detailed analysis of very weak fragments of modal logic. Our fragments lack connectives that introduce non-determinism and they feature restrictions on the modal operators, which may lead to substantial reductions in complexity. Our main result is a general game-based characterization of the expressive power of our fragments over the class of finite structures.

We provide a detailed analysis of very weak fragments of modal logic. Our fragments lack connectives that introduce nondeterminism and they feature restrictions on the modal operators, which may lead to substantial reductions in complexity. Our main result is a general game-based characterization of the expressive power of our fragments over the class of finite structures.

We study the relative succinctness and expressiveness of modal logics, and prove that these relationships can be as complex as any countable partial order. For this, we use two uniform formalisms to define modal operators, and obtain results on succinctness and expressiveness in these two settings. Our proofs are based on formula size games introduced by Adler and Immerman and bisimulations.

In this paper we present a general methodology to extend Defeasible Logic with modal operators. We motivate the reasons for this type of extension and we argue that the extension will allow for a robust knowledge framework in different application areas. The paper presents an extension of RuleML to capture Modal Defeasible Logic.