SHACL Validation in the Presence of Ontologies: Semantics and Rewriting Techniques

2025-07-16

AI Summary

This paper addresses the RDF data validation challenge arising from semantic conflicts between SHACL (which assumes the Closed World Assumption) and OWL ontologies (which assume the Open World Assumption). Methodologically, we restrict the ontology to the Horn-ALCHIQ fragment, construct a finitely representable core universal model thereof, and employ model rewriting to reduce ontology-aware SHACL validation to standard SHACL validation. Theoretically, we establish—for the first time under this setting—the computational complexity of the validation problem: combined complexity is EXPTIME-complete and data complexity is PTIME-complete. Practically, we deliver a semantically coherent and computationally feasible unified validation framework, effectively bridging the semantic gap between these two W3C standards.

Technology Category

• Knowledge Representation and Reasoning: Ontologies
• Constraint Satisfaction and Optimization: Satisfiability Modulo Theories
• Data Mining & Knowledge Management: Linked Open Data, Knowledge Graphs & KB Completion

Application Category

• Semantics and Knowledge: Scalable techniques for the creation, curation, publication, maintenance, and consumption of large, Web-based, structured, reusable, knowledge graphs and ontologies
• Graph Algorithms and Modeling for the Web: Foundation models and LLMs for Web-related graphs
• Security and Privacy: Data transparency and provenance

Abstract

SHACL and OWL are two prominent W3C standards for managing RDF data. These languages share many features, but they have one fundamental difference: OWL, designed for inferring facts from incomplete data, makes the open-world assumption, whereas SHACL is a constraint language that treats the data as complete and must be validated under the closed-world assumption. The combination of both formalisms is very appealing and has been called for, but their semantic gap is a major challenge, semantically and computationally. In this paper, we advocate a semantics for SHACL validation in the presence of ontologies based on core universal models. We provide a technique for constructing these models for ontologies in the rich data-tractable description logic Horn-ALCHIQ. Furthermore, we use a finite representation of this model to develop a rewriting technique that reduces SHACL validation in the presence of ontologies to standard validation. Finally, we study the complexity of SHACL validation in the presence of ontologies, and show that even very simple ontologies make the problem EXPTIME-complete, and PTIME-complete in data complexity.

Problem

• Bridging semantic gap between SHACL and OWL standards
• Developing rewriting technique for SHACL validation with ontologies
• Analyzing complexity of SHACL validation with ontologies

Innovation

• Advocates core universal models for SHACL validation
• Uses Horn-ALCHIQ for constructing ontology models
• Develops rewriting technique for standard validation