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Combination of disjoint theories: beyond decidability. (English) Zbl 1358.68253

Gramlich, Bernhard (ed.) et al., Automated reasoning. 6th international joint conference, IJCAR 2012, Manchester, UK, June 26–29, 2012. Proceedings. Berlin: Springer (ISBN 978-3-642-31364-6/pbk). Lecture Notes in Computer Science 7364. Lecture Notes in Artificial Intelligence, 256-270 (2012).
Summary: Combination of theories underlies the design of satisfiability modulo theories (SMT) solvers. The Nelson-Oppen framework can be used to build a decision procedure for the combination of two disjoint decidable stably infinite theories.
We here study combinations involving an arbitrary first-order theory. Decidability is lost, but refutational completeness is preserved. We consider two cases and provide complete (semi-) algorithms for them. First, we show that it is possible under minor technical conditions to combine a decidable (not necessarily stably infinite) theory and a disjoint finitely axiomatized theory, obtaining a refutationally complete procedure. Second, we provide a refutationally complete procedure for the union of two disjoint finitely axiomatized theories, that uses the assumed procedures for the underlying theories without modifying them.
For the entire collection see [Zbl 1245.68010].

MSC:

68T15 Theorem proving (deduction, resolution, etc.) (MSC2010)
03B25 Decidability of theories and sets of sentences
03B35 Mechanization of proofs and logical operations
03B62 Combined logics
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