Denotational Semantics for ODRL: Knowledge-Based Constraint Conflict Detection

arXiv (Cornell University)

Abstract

ODRL's six set-based operators -- isA, isPartOf, hasPart, isAnyOf, isAllOf, isNoneOf -- depend on external domain knowledge that the W3C specification leaves unspecified. Without it, every cross-dataspace policy comparison defaults to Unknown. We present a denotational semantics that maps each ODRL constraint to the set of knowledge-base concepts satisfying it. Conflict detection reduces to denotation intersection under a three-valued verdict -- Conflict, Compatible, or Unknown -- that is sound under incomplete knowledge. The framework covers all three ODRL composition modes (and, or, xone) and all three semantic domains arising in practice: taxonomic (class subsumption), mereological (part-whole containment), and nominal (identity). For cross-dataspace interoperability, we define order-preserving alignments between knowledge bases and prove two guarantees: conflicts are preserved across different KB standards, and unmapped concepts degrade gracefully to Unknown -- never to false conflicts. A runtime soundness theorem ensures that design-time verdicts hold for all execution contexts. The encoding stays within the decidable EPR fragment of first-order logic. We validate it with 154 benchmarks across six knowledge base families (GeoNames, ISO 3166, W3C DPV, a GDPR-derived taxonomy, BCP 47, and ISO 639-3) and four structural KBs targeting adversarial edge cases. Both the Vampire theorem prover and the Z3 SMT solver agree on all 154 verdicts. A key finding is that exclusive composition (xone) requires strictly stronger KB axioms than conjunction or disjunction: open-world semantics blocks exclusivity even when positive evidence appears to satisfy exactly one branch.

Authors 7

1. Daham Mohammed Mustafa Aachen

   Fraunhofer Institute for Applied Information Technology · RWTH Aachen University

   Affiliation as printed

   Fraunhofer FIT , Sankt Augustin , Germany

   RWTH Aachen University , Germany

2. Diego Collarana

   Fraunhofer Institute for Applied Information Technology

   Affiliation as printed

   Fraunhofer FIT , Sankt Augustin , Germany

3. Yixin Peng Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University , Germany

4. Rafiqul Haque

   Ollscoil na Gaillimhe – University of Galway

   Affiliation as printed

   University of Galway , Ireland

5. Christoph Lange-Bever Aachen

   Fraunhofer Institute for Applied Information Technology · RWTH Aachen University

   Affiliation as printed

   Fraunhofer FIT , Sankt Augustin , Germany

   RWTH Aachen University , Germany

6. Christoph Quix Aachen

   Fraunhofer Institute for Applied Information Technology · RWTH Aachen University

   Affiliation as printed

   Fraunhofer FIT , Sankt Augustin , Germany

   RWTH Aachen University , Germany

7. Stephan Decker Aachen

   Fraunhofer Institute for Applied Information Technology · RWTH Aachen University

   Affiliation as printed

   Fraunhofer FIT , Sankt Augustin , Germany

   RWTH Aachen University , Germany