Summary: A Logical Semantics for
Depth­First Prolog with Ground Negation
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James Andrews
Dept. of Computing Science
Simon Fraser University
Burnaby, BC, CANADA V5A 1S6
jamie@cs.sfu.ca
Tel. (604)291­3012
FAX (604)291­3045
Abstract: A sound and complete semantics is given for sequential, depth­first logic
programming with a version of negation as failure. The semantics is logical in the sense
that it is built up only from valuation functions (multi­valued logic interpretations in the
style of Fitting and Kunen) and logically­motivated equivalence relations between formulas.
The notion of predicate folding and unfolding with respect to a program (Tamaki, Sato,
Levi et al.) and the universal notion of ``disjunctive unfolding'' (Andrews) are important
elements of this semantics.
The negation used is the version which returns an error indication whenever it is invoked
on a non­ground goal. It is theoretically interesting that this form of negation, along with
the left­to­right processing of depth­first logic programming, can be characterized logically

Source: Andrews, Jamie - Department of Computer Science, University of Western Ontario

Collections: Computer Technologies and Information Sciences