ALGORITHM TRANSLATING RECURSIVE PROGRAMS INTO HORN SETS.

R. A. Kowalski has formulated the computations on Horn clause sets based on derivation of the first-order predicate logic, where the Horn clause set is regarded as a program and the input (unit) derivation controversy in the Horn clause set is regarded as a program and the input (unit) derivation controversy in the Horn clause set is regarded as the computation. This paper presents an algorithm for translating the recursive program into a Horn clause set so that the corresponding computations are equivalent, indicating that the computations in a recursive program can be represented by a Horn clause set. In the proposed translation algorithm, a Horn clause set must be constructed reflecting the computation rules of the recursive program. The paper adopts, as the computation rule of the recursive program, the parallel outermost rule, which is one of the fixed-point rules and one of those best ensuring stationarity. A technique is shown for the translation algorithm from the recursive program to Horn clause sets.