Concept and Role Forgetting in ALC Ontologies

Kewen Wang, Zhe Wang, Rodney Topor, Jeff Z. Pan, Grigoris Antoniou

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

36 Citations (Scopus)


Forgetting is an important tool for reducing ontologies by eliminating some concepts and roles while preserving sound and complete reasoning. Attempts have previously been made to address the problem of forgetting in relatively simple description logics (DLs) such as DL-Lite and extended εL. The ontologies used in these attempts were mostly restricted to TBoxes rather than general knowledge bases (KBs). However, the issue of forgetting for general KBs in more expressive description logics, such as ALC and OWL DL, is largely unexplored. In particular, the problem of characterizing and computing forgetting for such logics is still open. In this paper, we first define semantic forgetting about concepts and roles in ALC ontologies and state several important properties of forgetting in this setting. We then define the result of forgetting for concept descriptions in ALC , state the properties of forgetting for concept descriptions, and present algorithms for computing the result of forgetting for concept descriptions. Unlike the case of DL-Lite, the result of forgetting for an ALC ontology does not exist in general, even for the special case of concept forgetting. This makes the problem of how to compute forgetting in ALC more challenging. We address this problem by defining a series of approximations to the result of forgetting for ALC ontologies and studying their properties and their application to reasoning tasks. We use the algorithms for computing forgetting for concept descriptions to compute these approximations. Our algorithms for computing approximations can be embedded into an ontology editor to enhance its ability to manage and reason in (large) ontologies.

Original languageEnglish
Title of host publicationThe Semantic Web, ISWC 2009
Subtitle of host publication8th International Semantic Web Conference, ISWC 2009, Proceedings
EditorsAbraham Bernstein, David R. Karger, Tom Heath, Lee Feigenbaum, Diana Maynard, Enrico Motta, Krishnaprasad Thirunarayan
Place of PublicationBerlin
PublisherSpringer-Verlag Berlin Heidelberg
Number of pages16
Volume5823 LNCS
ISBN (Electronic)9783642049309
ISBN (Print)364204929X, 9783642049293
Publication statusPublished - 8 Oct 2009
Externally publishedYes
Event8th International Semantic Web Conference - Chantilly, United States
Duration: 25 Oct 200929 Oct 2009
Conference number: 8

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
PublisherSpringer-Verlag Berlin Heidelberg
Volume5823 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference8th International Semantic Web Conference
Abbreviated titleISWC 2009
Country/TerritoryUnited States


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