HermiT

HermiT is a high-performance Java-based reasoner for ontologies using the Web Ontology Language (OWL).

Developed by the University of Oxford, HermiT is the first publicly available OWL reasoner built on a novel hypertableau calculus. This specific algorithm allows it to classify complex ontologies (like FMA or GALEN) in seconds, tasks that often stall or crash traditional tableau-based systems. It fully supports the OWL 2 standard, integrates natively with the OWL API, and comes pre-installed as a core reasoning engine in the Protégé ontology editor. Whether running via command line or as a Java library, HermiT provides consistent, efficient validation of ontology consistency and class subsumption.

https://www.hermit-reasoner.com/