The SLD finite failure set
Christopher John Hogger · 1990
Abstract In this Theme we introduce the notion of a finite failure set. Relative to a given program P and a given inference system, this set comprises exactly those ground atoms q for which the query ?q finitely fails. We shall restrict our attention throughout to the case where Pis definite and the inference system is SLD. Once we know what the finite failure set is relative to SLD inference, we shall also be able to say something about the execution by SLDNF of queries containing fail calls-subject, of course, to the assumption that the chosen computation rule is safe. We shall not say anything in this Theme about the more general situation where fail calls may occur also in clause bodies, for the position then is significantly more complicated.