Finite-Cliquewidth Sets of Existential Rules textendash Toward a General Criterion for Decidable yet Highly Expressive Querying

Publikation: Beitrag in Buch/Konferenzbericht/Sammelband/GutachtenBeitrag in KonferenzbandBeigetragenBegutachtung

Beitragende

Abstract

In our pursuit of generic criteria for decidable ontology-based querying, we introduce finite-cliquewidth sets (fcs) of existential rules, a model-theoretically defined class of rule sets, inspired by the cliquewidth measure from graph theory. By a generic argument, we show that fcs ensures decidability of entailment for a sizable class of queries (dubbed DaMSOQs) subsuming conjunctive queries (CQs). The fcs class properly generalizes the class of finite-expansion sets (fes), and for signatures of arity ≤2, the class of bounded-treewidth sets (bts). For higher arities, bts is only indirectly subsumed by fcs by means of reification. Despite the generality of fcs, we provide a rule set with decidable CQ entailment (by virtue of first-order-rewritability) that falls outside fcs, thus demonstrating the incomparability of fcs and the class of finite-unification sets (fus). In spite of this, we show that if we restrict ourselves to single-headed rule sets over signatures of arity ≤2, then fcs subsumes fus.

Details

OriginalspracheEnglisch
TitelProceedings of the 26th International Conference on Database Theory (ICDT 2023)
Redakteure/-innenFloris Geerts, Brecht Vandevoort
Herausgeber (Verlag)Schloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing
Seiten18:1-18:18
ISBN (elektronisch)9783959772709
PublikationsstatusVeröffentlicht - 1 März 2023
Peer-Review-StatusJa

Publikationsreihe

ReiheLeibniz international proceedings in informatics : LIPIcs
Band255
ISSN1868-8969

Externe IDs

Scopus 85150686731
ORCID /0000-0003-3214-0828/work/173054743

Schlagworte

ASJC Scopus Sachgebiete

Schlagwörter

  • TGDs, bounded-treewidth sets, cliquewidth, datalog, existential rules, finite-unification sets, first-order rewritability, monadic second-order logic, treewidth