A Base for Achieving Semantics for Prolog with Cut for 'Correct' Observables

摘要

Decorated tree semantics is a goal-independent denotational semantics for Prolog that deals with the control rules of Prolog and cut operator. This semantics was designed with the aim to provide a general framework for abstract analysis of generic properties of logic programs and has been specialized into computed answer (ca) semantics and call pattern (cp) semantics. In this paper we show that the methods for achieving semantics for the "correct" observables (i.e. observables related to successful derivations), correct partial answers (cpa) and correct call patterns (ccp) in particular, are not trivial extensions of the methods for achieving ca and cp semantics. We extend the work in [13] and propose a two-step method for achieving cpa and ccp semantics using the theory of abstract interpretation. This paper is concerned with the first step, where the main result is a modified decorated tree semantics that serves as a base for further abstraction to get cpa and ccp semantics.