In computer science and artificial intelligence, ontology languages are formal languages used to construct ontologies. They allow the encoding of knowledge about specific domains and often include reasoning rules that support the processing of that knowledge. Ontology languages are usually declarative languages, are almost always generalizations of frame languages, and are commonly based on either first-order logic or on description logic.
Classification of ontology languages
Classification by syntax
Traditional syntax ontology languages Common Logic - and its dialects CycL DOGMA (Developing Ontology-Grounded Methods and Applications) F-Logic (Frame Logic) FO-dot (First-order logic extended with types, arithmetic, aggregates and inductive definitions) KIF (Knowledge Interchange Format) Ontolingua based on KIF KL-ONE KM programming language LOOM (ontology) OCML (Operational Conceptual Modelling Language) OKBC (Open Knowledge Base Connectivity) PLIB (Parts LIBrary) RACER
Markup ontology languages These languages use a markup scheme to encode knowledge, most commonly with XML.
DAML+OIL Ontology Inference Layer (OIL) Web Ontology Language (OWL) Resource Description Framework (RDF) RDF Schema (RDFS) SHOE
Controlled natural languages Attempto Controlled English
Open vocabulary natural languages Executable English
Classification by structure (logic type)
Frame-based Three languages are completely or partially frame-based languages.
F-Logic OKBC KM
Description logic-based Description logic provides an extension of frame languages, without going so far as to take the leap to first-order logic and support for arbitrary predicates.
KL-ONE RACER OWL Gellish is an example of a combined ontology language and ontology that is description logic-based. It distinguishes between the semantic differences among others of:
relation types for relations between concepts (classes) relation types for relations between individuals relation types for relations between individuals and classes It also contains constructs to express queries and communicative intent.
First-order logic-based Several ontology languages support expressions in first-order logic and allow general predicates.
Common Logic CycL FO-dot (first-order logic extended with types, arithmetic, aggregates and inductive definitions) KIF
See also Domain theory Formal concept analysis Galois connection Lattice (order) Modeling language OntoUML
Notes
References Oscar Corcho, Asuncion Gomez-Perez, A Roadmap to Ontology Specification Languages (2000) Introduction to Description Logics – DL course by Enrico Franconi, Faculty of Computer Science, Free University of Bolzano, Italy
