Unions of non-disjoint theories and combinations of satisfiability procedures
In this paper we outline a theoretical framework for the combination of decision procedures for constraint satistiability. We describe a general combination method which, given a procedure that decides constraint satisfiability with respect to a constraint theory T(1) and one that decides constraint satisfiability with respect to a constraint theory T(2), produces a procedure that (semi-)decides constraint satisfiability with respect to the union of T(1) and T(2). We provide a number of model-theoretic conditions on the constraint language and the component constraint theories for the method to be sound and complete, with special emphasis on the case in which the signatures of the component theories are non-disjoint. We also describe some general classes of theories to which our combination results apply, and relate our approach to some of the existing combination methods in the field. (C) 2002 Elsevier Science B.V. All rights reserved.
combination of satisfiability procedures decision problems constraint-based reasoning automated deduction