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On Signings and the Well-Founded Semantics

Published online by Cambridge University Press:  20 April 2021

MICHAEL J. MAHER Open the ORCID record for MICHAEL J. MAHER [Opens in a new window]
MICHAEL J. MAHER*
Affiliation:
Reasoning Research Institute, Canberra, Australia (e-mail: michael.maher@reasoning.org.au)
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Abstract

In this note, we use Kunen’s notion of a signing to establish two theorems about the well-founded semantics of logic programs, in the case where we are interested in only (say) the positive literals of a predicate p that are consequences of the program. The first theorem identifies a class of programs for which the well-founded and Fitting semantics coincide for the positive part of p. The second theorem shows that if a program has a signing, then computing the positive part of p under the well-founded semantics requires the computation of only one part of each predicate. This theorem suggests an analysis for query answering under the well-founded semantics. In the process of proving these results, we use an alternative formulation of the well-founded semantics of logic programs, which might be of independent interest.

Keywords

signingwell-founded semanticsquery optimization
Type
Technical Note
Information
Theory and Practice of Logic Programming , Volume 22 , Issue 1 , January 2022 , pp. 115 - 127
Copyright
© The Author(s), 2021. Published by Cambridge University Press

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Footnotes

*

The author has an adjunct position at Griffith University and an honorary position at UNSW. He thanks the referees for comments that helped improve this paper.

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