Equational problems anddisunification
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Journal of the ACM (JACM)
Theorem proving with ordering and equality constrained clauses
Journal of Symbolic Computation
The resolution calculus
Extending Resolution for Model Construction
JELIA '90 Proceedings of the European Workshop on Logics in AI
Decision Procedures Using Model Building Techniques
CSL '95 Selected Papers from the9th International Workshop on Computer Science Logic
A Method for Building Models Automatically. Experiments with an Extension of OTTER
CADE-12 Proceedings of the 12th International Conference on Automated Deduction
Extending semantic resolution via automated model building: applications
IJCAI'95 Proceedings of the 14th international joint conference on Artificial intelligence - Volume 1
Extending Decidable Clause Classes via Constraints
Selected Papers from Automated Deduction in Classical and Non-Classical Logics
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. In [6], a resolution-based inference system on c-clauses (i.e. constrained clauses) was introduced, incorporating powerful deletion rules for redundancy elimination. This inference system was extended to resolution refinements in subsequent papers of Caferra et al. (e.g. [4] and [5]). The completeness proofs given for the purely refutational calculi (i.e.: the inference systems without deletion rules) are basically "translations" of the corresponding results from standard clause logic to constrained clause logic (= c-clause logic, for short). This work focuses on the deletion rules of the calculi of Caferra et al. and, in particular, on the c-dissubsumption rule, which is considerably more powerful than the usual subsumption concept in standard clause logic. We will show that the "conventional" method for proving the completeness of (standard clause) resolution refinements with subsumption fails when the powerful deletion rules of Caferra et al. are considered. Therefore, in order to prove the completeness of the c-clause calculi, a different strategy is required. To this end, we shall extend the well-known concept of semantic trees from standard clause logic to c-clause logic. In general, purely non-deterministic application of the inference rules is not sufficient to ensure refutational completeness. It is intuitively clear, that some sort of "fairness" must be required. The completeness proof via semantic trees gives us a hint for defining precisely what it means for a rule application strategy to be "fair". Finally other methods for proving completeness and defining redundancy criteria are contrasted with completeness via semantic trees and c-dissubsumption. In particular, it is shown that the redundancy criteria within the ordering-based approaches of Bachmair/Ganzinger (cf. [2]) and Nieuwenhuis/Rubio (cf. [11]) are incomparable with c-dissubsumption.