Abstract
The problem of computational completeness of Horn clause logic programs is revisited. The standard results on representability of all computable predicates by Horn clause logic programs are not related to the real universe on which logic programs operate. SLD-resolution, which is the main mechanism to execute logic programs, may give answer substitutions with variables. As the main result we prove that computability by Horn clause logic programs is equivalent to standard computability over the Herbrand universe with variables. The semantics we use isS-semantics introduced by Falaschi et al. [3]. As an application of the main result we prove the existence of a metainterpreter for a sublanguage of real Prolog, written in the language of Horn clauses with the S-semantics. We also show that the traditional semantics of Prolog do not reflect its computational behavior from the viewpoint of recursion theory.
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References
H. Andréka and I. Németi, The generalized completeness of horn clause logic seen as a programming language, Acta Cybernetica 4 (1978) 3–10.
Yu.L. Ershov,Theory of Enumerations (in Russian) (Nauka, 1977).
M. Falaschi, G. Levi, M. Martelli, and C. Palamidessi, Declarative modeling of the operational behavior of logic languages, Theor. Comp. Sci. 69(3) (1989) 298–318.
L. Henshen and L. Wos, Unit refutation and Horn sets, J. ACM 21 (1974) 590–605.
P.M. Hill and J.W. Lloyd, The Gödel report, Technical Report TR-91-02, Univ. of Bristol, Department of Computer Science (1991).
Matiyasevič, The diophantiness of recursively enumerable sets (in Russian), Sov. Math. Doklady (1970) 279–282.
M. Minsky,Computation: Finite and Infinite Machines (Prentice Hall, 1967).
H. Rogers,Theory of Recursive Functions and Effective Computability (McGraw Hill, 1967).
P. Štěpánek and J. Šebelík, Horn clause programs for recursive functions, in K.L. Clark and S.-Å. Tärnlund, editors,Logic Programming (Academic Press, 1982) pp. 325–340.
J.C. Sheperdson, Negation in logic programming, in J. Minker, editor,Deductive Databases and Logic Programming (Morgan Kaufmann, 1988) pp. 19–88.
E. Shapiro, A family of concurrent logic programming languages, ACM Comput. Surveys 21(3) (1989) 412–510.
S.-Å. Tärnlund, Horn clause computability, BIT 17 (1977) 215–216.
A. Voronkov, On computability by logic programs, in H. Blair, W. Marek, A. Nerode, and J. Remmel, editors,Proceedings of the Workshop on Structural Complexity and Recursion-Theoretic Methods in Logic Programming (Washington, D.C., 1992) pp. 165–174.
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This article is a revised version of [13]. The work was essentially done during author's visit to ECRC.
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Voronkov, A. On computability by logic programs. Ann Math Artif Intell 15, 437–456 (1995). https://doi.org/10.1007/BF01536404
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DOI: https://doi.org/10.1007/BF01536404