Similarity-based SLD resolution and its implementation in an extended Prolog system

This paper presents an extension of SLD resolution towards approximate reasoning. The proposed refutation procedure overcomes failures in the unification process by exploiting similarity relation defined between predicate and constant symbols. This enables to compute approximate solutions, with an associated approximation degree, when failures of the exact inference process occur. In this paper we outline the main ideas of this approach and we present an extended PROLOG interpreter, named SiLog, which implements this inference procedure.