The paper is a general overview of an approach to the semantics of logic programs whose aim is finding notions of models which really capture the operational semantics, and are therefore useful for defining program equivalences and for semantics-based program analysis. The approach leads

to investigate the power of this approach. First, we introduce a new semantics for such programs based on ideals of lattices. Subsequently, some proposals for multivalued logic programming [5, 7, 32, 47, 40, 18] as well as some formalisms for temporal reasoning [1, 3, 42] are shown to fit into this framework

applications and services. The agents support considerations of semantics and quality of service (QoS). They interact and share information, in essence creating an ecosystem of collaborative service providers and consumers. Consequently, our approach enables applications to be dynamically configured at runtime

With the development of the semantic web activity, ontologies become widely used to represent the conceptualization of a domain. However, none of the existing ontology languages provides a means to capture uncertainty about the concepts, properties and instances in a domain. Probability theory is a

and rules of inference. Both natural deduction and sequent calculi are allowed. Isabelle's approach is to represent the various formal systems, or object-logics, within a single meta-logic. The meta-logic is a fragment of higher-order logic, formulated in natural deduction. The proof theory of meta

to interpret terms associated with substitution like pairing for \Sigma -types or application for \Pi-types one needs a semantical equivalent to syntactic substitution. To clarify the issue let us have a look at the "naive" approach described in Seely's seminal paper [14] which contains a subtle

. Applications of the proposed approach include several natural proof obligations for modular termination proofs, decidability results for the least term model semantics and S-semantics. Keywords. Termination, recurrent and acceptable programs, rst order theories, least term model semantics, S-semantics. 1

, scalability of the ontology engineering process and methodology, efficient and effective ontology storage and management, and coexistence of heterogeneous rule systems that surround an ontology mediating between it and application agents. Ontologies should represent a domain's semantics independently

. This paper presents dialectical proof theories for Dung's preferred semantics of defeasible argumentation. The proof theories have the form of argument games for testing membership of some (credulous reasoning) or all preferred extensions (sceptical reasoning). The credulous proof theory

their own decision-theoretic model of the world, including beliefs about its environment and recursive models of other agents. Using these quantitative models of uncertainty and preferences, we have translated existing psychological theories into a decision-theoretic semantics that allow the agents