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Mauro Ferrari

Publications and source records attributed to Mauro Ferrari.

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A G\"odel Modal Logic Over Witnessed Models

We introduce GW, a G\"odel modal logic based on Kripke models in which the value of each modal formula is witnessed by an accessible world. This witnessed semantics eliminates the limit-based phenomena that preclude the finite model property in the usual Kripke semantics for G\"odel modal logics, thereby yielding a more constructive semantic framework. We present a sound and complete refutation calculus for GW and design a terminating backward proof-search procedure with countermodel generation. As a direct consequence of this procedure, GW enjoys the finite model property.

cs.LO

Duality between unprovability and provability in forward proof-search for Intuitionistic Propositional Logic

The inverse method is a saturation based theorem proving technique; it relies on a forward proof-search strategy and can be applied to cut-free calculi enjoying the subformula property. Here we apply this method to derive the unprovability of a goal formula G in Intuitionistic Propositional Logic. To this aim we design a forward calculus FRJ(G) for Intuitionistic unprovability which is prone to constructively ascertain the unprovability of a formula G by providing a concise countermodel for it; in particular we prove that the generated countermodels have minimal height. Moreover, we clarify the role of the saturated database obtained as result of a failed proof-search in FRJ(G) by showing how to extract from such a database a derivation witnessing the Intuitionistic validity of the goal.

math.LO

A Note on Semantic Web Services Specification and Composition in Constructive Description Logics

The idea of the Semantic Web is to annotate Web content and services with computer interpretable descriptions with the aim to automatize many tasks currently performed by human users. In the context of Web services, one of the most interesting tasks is their composition. In this paper we formalize this problem in the framework of a constructive description logic. In particular we propose a declarative service specification language and a calculus for service composition. We show by means of an example how this calculus can be used to define composed Web services and we discuss the problem of automatic service synthesis.

cs.AI