Lp2normal — A normalization tool for extended logic programs

Jori Bomanson*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

13 Citations (Scopus)


Answer set programming (ASP) features a rich rule-based modeling language for encoding search problems. While normal rules form the simplest rule type in the language, various forms of extended rules have been introduced in order to ease modeling of complex conditions and constraints. Normalization means replacing such extended rules with identically functioning sets of normal rules. In this system description, we present lp2normal, which is a state-of-the-art normalizer that acts as a filter on ground logic programs produced by grounders, such as gringo. It provides options to translate away choice rules, cardinality rules, and weight rules, and to rewrite optimization statements using comparable techniques. The produced logic programs are suitable inputs to tools that lack support for extended rules, in particular. We give an overview of the normalization techniques currently supported by the tool and summarize its features. Moreover, we discuss the typical application scenarios of normalization, such as when implementing the search for answer sets using a back-end solver without direct support for cardinality constraints or pseudo-Boolean constraints.

Original languageEnglish
Title of host publicationLogic Programming and Nonmonotonic Reasoning
Subtitle of host publication14th International Conference, LPNMR 2017, Espoo, Finland, July 3-6, 2017, Proceedings
Number of pages7
ISBN (Print)9783319616599
Publication statusPublished - 2017
MoE publication typeA4 Conference publication
EventInternational Conference on Logic Programming and Nonmonotonic Reasoning - Espoo, Finland
Duration: 3 Jul 20176 Jul 2017
Conference number: 14

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


ConferenceInternational Conference on Logic Programming and Nonmonotonic Reasoning
Abbreviated titleLPNMR


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