Evaluating the Generality of Disjunctive Model Faithful Acyclicity on OWL ontologies

Theses

• Suggested Thesis Topics
• Completed Theses
  • Algebra und Diskrete Strukturen
  • Automatentheorie
  • Computational Logic
  • Knowledge-aware Artificial Intelligence
  • Logische Programmierung und Argumentation
  • Verifikation und formale quantitative Analyse
  • Wissensbasierte Systeme
• Currently Ongoing Theses

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Evaluating the Generality of Disjunctive Model Faithful Acyclicity on OWL ontologies

project thesis by Lukas Gerlach

•   Supervisor Markus Krötzsch, David Carral
•   Wissensbasierte Systeme
•   1 Oktober 2020 – 31 März 2021
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The chase is a well-studied, sound and complete algorithm that is used in different variants as a basis for reasoning tasks over (disjunctive) existential rules. Since termination of the chase is undecidable, acyclicity notions, i.e. sufficient conditions for termination, like model faithful acyclicity (MFA) for the skolem chase and restricted model faithful acyclicity (RMFA) for the restricted chase are introduced. The recently developed acyclicity notion disjunctive model faithful acyclicity (DMFA) for the disjunctive skolem chase promises improvements for detecting termination over existing notions like MFA in theory. We further know that RMFA captures DFMA while RMFA itself is not sound for the disjunctive skolem chase.

We evaluate the generality of DMFA in practice compared to MFA and RMFA on rule sets that we obtain from real-world OWL ontologies in the Oxford ontology repository (OXFD) and the dataset of the OWL reasoner evaluation 2015 (ORE15). Our results show that DMFA achieves practical improvements over MFA that narrow the gap towards RMFA. Our findings motivate further research regarding the disjunctive skolem chase in general and the development of sufficient conditions for non-termination of the disjunctive skolem chase in particular.