... theproblem of finding a proof of a first-order formula to the problem of finding aproof of a simpler type of formula, called a proposition. Propositions are muchsimpler than first-order formulae. ... 4119.2.2 GCNF-Proofs in SLD-Form, 4139.2.3 Completeness of Proofs in SLD-Form, 413PROBLEMS, 4219.3 SLD-Resolution in Propositional Logic, 4229.3.1 SLD-Derivations and SLD-Refutations, 4229.3.2 ... general method for first-order logic.However, there is another familiar method for testing whether a formulais true: to give a proof of this formula. Of course, to be of any value, a proof system...