Fabio Papacchini

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Model generation and minimal model generation is useful for fault analysis, verification of systems and validation of data models. Whereas for classical propositional and first-order logic several model minimization approaches have been developed and studied, for non-classical logic the topic has been much less studied. In this paper we introduce a minimal(More)
Model generation and minimal model generation are useful for tasks such as model checking and for debugging of logical specifications. This paper presents terminating procedures for the generation of models minimal modulo subset-simulation for the modal logic K and all combinations of extensions with the axioms T, B, D, 4 and 5. Our procedures are minimal(More)
In this paper we propose a novel minimality criterion for models of modal logics based on a variation of the notion of simulation, called subset-simulation. We present a minimal model sound and complete tableau calculus for the generation of this new kind of minimal models for the multi-modal logic K(m), and we discuss extensions to cover more expressive(More)
We study the complexity of ontology-mediated querying when ontologies are formulated in the guarded fragment of first-order logic (GF). Our general aim is to classify the data complexity on the level of ontologies where query evaluation w.r.t. an ontology O is considered to be in PTime if all (unions of conjunctive) queries can be evaluated in PTime w.r.t.(More)
We study the following question: if T is a TBox that is formulated in an expressive DL L and all CQs can be evaluated in PTime w.r.t. T , can T be replaced by a TBox T ′ that is formulated in the Hornfragment of L and such that for all CQs and ABoxes, the answers w.r.t. T and T ′ coincide? Our main results are that this is indeed the case when L is the set(More)
We study the following question: if T is a TBox that is formulated in an expressive DL L and all CQs can be evaluated in PTime w.r.t. T , can T be replaced by a TBox T ′ that is formulated in the Horn-fragment of L and such that for all CQs and ABoxes, the answers w.r.t. T and T ′ coincide? Our main results are that this is indeed the case when L is the set(More)
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