XSB: A system for efficiently computing well-founded semantics

Prasad Rao, Konstantinos Sagonas, Terrance Swift, David S. Warren, Juliana Freire

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The well-founded model provides a natural and robust semantics for logic programs with negative literals in rule bodies. We implemented the well-founded semantics in the SLG-WAM of XSB [19]. Performance results indicate that the overhead of delay and simplification to Prolog-or tabled-evaluations is minimal. To compute the well-founded semantics, the SLG-WAM adds to an efficient tabling engine for definite programs three operations-negative loop detection, delay and simplification-which serve to detect, to break and to resolve cycles through negation that might arise in evaluating normal programs. XSB is a full Prolog system that closely approximates the ISO standard; additionally, it supports a tight integration of tabled predicates with nontabled predicates.

Original languageEnglish (US)
Title of host publicationLogic Programming and Nonmonotonic Reasoning - 4th International Conference, LPNMR 1997, Proceedings
EditorsJurgen Dix, Ulrich Furbach, Anil Nerode
PublisherSpringer Verlag
Number of pages10
ISBN (Print)9783540632559
StatePublished - 1997
Event4th International Conference on Logic Programming and Non-Monotonic Reasoning, LPNMR 1997 - Dagstuhl Castle, Germany
Duration: Jul 28 1997Jul 31 1997

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Other4th International Conference on Logic Programming and Non-Monotonic Reasoning, LPNMR 1997
CityDagstuhl Castle

ASJC Scopus subject areas

  • Theoretical Computer Science
  • General Computer Science


Dive into the research topics of 'XSB: A system for efficiently computing well-founded semantics'. Together they form a unique fingerprint.

Cite this