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Answering regular path queries in expressive description logics: An automata-theoretic approach (2007)
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| Venue: | In Proc. of the 22nd Nat. Conf. on Artificial Intelligence (AAAI 2007 |
| Citations: | 51 - 20 self |
BibTeX
@INPROCEEDINGS{Calvanese07answeringregular,
author = {Diego Calvanese},
title = {Answering regular path queries in expressive description logics: An automata-theoretic approach},
booktitle = {In Proc. of the 22nd Nat. Conf. on Artificial Intelligence (AAAI 2007},
year = {2007},
pages = {ee.lbl.gov/ns/.}
}
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Abstract
Expressive Description Logics (DLs) have been advocated as formalisms for modeling the domain of interest in various application areas. An important requirement is the ability to answer complex queries beyond instance retrieval, taking into account constraints expressed in a knowledge base. We consider this task for positive existential path queries (which generalize conjunctive queries and unions thereof), whose atoms are regular expressions over the roles (and concepts) of a knowledge base in the expressive DL ALCQIbreg. Using techniques based on two-way tree-automata, we first provide an elegant characterization of TBox and ABox reasoning, which gives us also a tight EXPTIME bound. We then prove decidability (more precisely, a 2EXPTIME upper bound) of query answering, thus significantly pushing the decidability frontier, both with respect to the query language and the considered DL. We also show that query answering is EXP-SPACE-hard already in rather restricted settings.
Keyphrases
expressive description logic regular path query automata-theoretic approach knowledge base query answering elegant characterization abox reasoning decidability frontier complex query instance retrieval regular expression tight exptime bound restricted setting expressive dl alcqibreg conjunctive query various application area important requirement union thereof two-way tree-automata positive existential path query query language account constraint upper bound
