In the present paper we use the approach of height functions to de ning a semi distance measure between Horn clauses This appraoch is already discussed elsewhere in the framework of propositional and sim ple rst order languages atoms Hereafter we prove its applicability for Horn clauses We use some basic results from lattice theory and introduce a family of language independent coverage based h...

A knowledge base is redundant if it contains parts that can be inferred from the rest of it. We study the problem of checking whether a CNF formula (a set of clauses) is redundant, that is, it contains clauses that can be derived from the other ones. Any CNF formula can be made irredundant by deleting some of its clauses: what results is an irredundant equivalent subset (I.E.S.) We study the co...

It is well known that the general problem of checking the satissability of a set of clauses is NP-complete. Experimentations have shown that there is a threshold on the ratio \number of clauses/number of variables" that separates the set of clauses for which a solution can be (easily) found from those for which it is impossible to nd a solution. The subject of this talk is the r-SAT problem, in...

We give a set of inference rules with constant constraints. Then we show how to extend a set of equational clauses, so that if the application of these inference rules halts on these clauses, then the theory is decidable by applying a standard set of Paramodulation inference rules. In addition, we can determine the number of clauses generated in this decision procedure. For some theories, such ...

A knowledge base is redundant if it contains parts that can be inferred from the rest of it. We study the problem of checking whether a CNF formula (a set of clauses) is redundant, that is, it contains clauses that can be derived from the other ones. Any CNF formula can be made irredundant by deleting some of its clauses: what results is an irredundant equivalent subset (I.E.S.) We study the co...

Constrained Horn clauses have proven to be a natural intermediate language for logically characterizing program semantics and reasoning about program behavior. In this paper, we present probabilistically constrained Horn clauses (pchc), which incorporate probabilistic variables inside otherwise traditional constrained Horn clauses. pchc enable reasoning about probabilistic programs by encoding ...

This paper presents a novel analysis of so-called gapless relative clause constructions such as Mandarin xiangpi ranshao de weidao (literally, ‘the smell that rubber burns’). Such constructions have been observed in East Asian languages. It is claimed that the Head noun of such relative clauses are relational nouns, and the clauses are their licensors. Syntactically, the Head nouns are predicat...

Recent work in functional and cognitive linguistics has argued and presented evidence that the positioning of adverbial clauses is motivated by competing pressures from syntactic parsing, discourse pragmatics, and semantics. Continuing this line of research, the current paper investigates the e¤ect of the iconicity principle on the positioning of temporal adverbial clauses. The iconicity princi...

In the area of inductive learning, generalization is the main operation, and the usual definition of induction is based on logical implication. Plotkin's well-known technique for computing least general generalizations of clauses under θ-subsumption sometimes produces results which are too general with respect to implication. Muggleton has shown that this problem only occurs in one type of gene...

Sentence-initial temporal clauses headed by before, as in "Before the scientist submitted the paper, the journal changed its policy", have been shown to elicit sustained negative-going brain potentials compared to maximally similar clauses headed by after, as in "After the scientist submitted the paper, the journal changed its policy". Such effects may be due to either one of two potential caus...