Proving Failure of Queries for Definite Logic Programs Using XSB-Prolog

Abstract

Proving failure of queries for definite logic programs can be done by constructing a finite model of the program in which the query is false. A general purpose model generator for first order logic can be used for this. A recent paper presented at PLILP98 shows how the peculiarities of definite programs can be exploited to obtain a better solution. There a procedure is described which combines abduction with tabulation and uses a meta-interpreter for heuristic control of the search. The current paper shows how similar results can be obtained by direct execution under the standard tabulation of the XSB-Prolog system. The loss of control is compensated for by better intelligent backtracking and more accurate failure analysis.