According to rumors, the early hybrids of object-oriented and deductive languages were mutants that escaped from secret Government AI labs. Whether this is true or not, the fact is that by mid-80's, database and logic programming communities began to take notice. The temptation was hard to resist: the object-oriented paradigm provides a better way of manipulating structured objects, while logic...

The properties of deductive systems in Hilbert algebras are treated. If a Hilbert algebra H considered as an ordered set is an upper semilattice then prime deductive systems coincide with meet-irreducible elements of the lattice DedH of all deductive systems on H and every maximal deductive system is prime. Complements and relative complements of DedH are characterized as the so called annihila...

This paper presents a technique for further applications of deductive databases in the eld of natural language processing. Although there were enormous research eeorts on analyzing the semantics of natural languages (NL), especially using Montague grammars (PTQ) for Prolog, corresponding programs for deductive databases are still missing, since range restriction is required in nearly all deduct...

We describe the theory and implementation of a general theorem-proving technique for checking integrity of deductive databases recently proposed by Sadri and Kowalski. The method uses an extension of the SLDNF proof procedure and achieves the effect of the simplification algorithms of Nicolas, Lloyd, Topor et al, and Decker by reasoning forwards from the update and thus focusing on the relevant...