🤖 AI Summary
This paper investigates the ontology fitting problem in description logic, given positive and negative ABox-query examples—where positives are ABoxes entailed by the ontology together with the query, and negatives are not. The goal is to construct a logically consistent ALC or ALCI ontology satisfying these constraints. We provide the first precise complexity characterizations for the existence of such ontologies: for atomic queries (AQ) and full conjunctive queries (CQ), the problem is CO-NP-complete; for general CQs and unions of CQs (UCQs), it is 2EXPTIME-complete—both in ALC and ALCI. Furthermore, we establish a unified satisfiability characterization and decision framework applicable across multiple query languages. This work delivers the first formal foundation for ontology-driven automated knowledge acquisition that is both theoretically complete and expressive across a broad spectrum of query languages.
📝 Abstract
We study a fitting problem inspired by ontology-mediated querying: given a collection
of positive and negative examples of
the form $(mathcal{A},q)$ with
$mathcal{A}$ an ABox and $q$ a Boolean query, we seek
an ontology $mathcal{O}$ that satisfies $mathcal{A} cup mathcal{O} vDash q$ for all positive examples and $mathcal{A} cup mathcal{O}
otvDash q$ for all negative examples.
We consider the description logics $mathcal{ALC}$ and $mathcal{ALCI}$ as ontology languages and
a range of query languages that
includes atomic queries (AQs), conjunctive queries (CQs), and unions thereof (UCQs).
For all of the resulting fitting problems,
we provide
effective characterizations and determine the computational complexity
of deciding whether a fitting ontology exists. This problem turns out to be ${small CO}NP$ for AQs and full CQs
and $2E{small XP}T{small IME}$-complete for CQs and UCQs.
These results hold for both $mathcal{ALC}$ and $mathcal{ALCI}$.