computer science Computer science is the study of computation, information, and automation. Computer science spans Theoretical computer science, theoretical disciplines (such as algorithms, theory of computation, and information theory) to Applied science, ...

and

artificial intelligence Artificial intelligence (AI) is the capability of computer, computational systems to perform tasks typically associated with human intelligence, such as learning, reasoning, problem-solving, perception, and decision-making. It is a field of re ...

, ontology languages are

formal language In logic, mathematics, computer science, and linguistics, a formal language is a set of strings whose symbols are taken from a set called "alphabet". The alphabet of a formal language consists of symbols that concatenate into strings (also c ...

s used to construct

ontologies In information science, an ontology encompasses a representation, formal naming, and definitions of the categories, properties, and relations between the concepts, data, or entities that pertain to one, many, or all domains of discourse. More ...

. 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 language In computer science, declarative programming is a programming paradigm—a style of building the structure and elements of computer programs—that expresses the logic of a computation without describing its control flow. Many languages that app ...

s, are almost always generalizations of

frame language Frames are an artificial intelligence data structure used to divide knowledge into substructures by representing "stereotyped situations". They were proposed by Marvin Minsky in his 1974 article "A Framework for Representing Knowledge". Frames are ...

s, and are commonly based on either

first-order logic First-order logic, also called predicate logic, predicate calculus, or quantificational logic, is a collection of formal systems used in mathematics, philosophy, linguistics, and computer science. First-order logic uses quantified variables over ...

or on

description logic Description logics (DL) are a family of formal knowledge representation languages. Many DLs are more expressive than propositional logic but less expressive than first-order logic. In contrast to the latter, the core reasoning problems for DLs are ...

Classification of ontology languages

Classification by syntax

Traditional syntax ontology languages

* Common Logic - and its dialects *

CycL CycL in computer science and artificial intelligence, is an ontology language used by Douglas Lenat's Cyc artificial intelligence project. Ramanathan V. Guha was instrumental in designing early versions of the language. A close CycL variant exi ...

DOGMA Dogma, in its broadest sense, is any belief held definitively and without the possibility of reform. It may be in the form of an official system of principles or doctrines of a religion, such as Judaism, Roman Catholicism, Protestantism, or Islam ...

(Developing Ontology-Grounded Methods and Applications) *

F-Logic F-logic (Frame logic) is a knowledge representation and ontology language. It combines the advantages of conceptual modeling with Object-oriented programming, object-oriented, Frame (artificial intelligence), frame-based languages, and offers a Decl ...

(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 Extensible Markup Language (XML) is a markup language and file format for storing, transmitting, and reconstructing data. It defines a set of rules for encoding electronic document, documents in a format that is both human-readable and Machine-r ...

. *

DAML+OIL The Web Ontology Language (OWL) is a family of knowledge representation languages for authoring ontologies. Ontologies are a formal way to describe taxonomies and classification networks, essentially defining the structure of knowledge for vario ...

* Ontology Inference Layer (OIL) *

Web Ontology Language The Web Ontology Language (OWL) is a family of Knowledge representation and reasoning, knowledge representation languages for authoring Ontology (information science), ontologies. Ontologies are a formal way to describe Taxonomy, taxonomies and ...

(OWL) *

Resource Description Framework The Resource Description Framework (RDF) is a method to describe and exchange graph data. It was originally designed as a data model for metadata by the World Wide Web Consortium (W3C). It provides a variety of syntax notations and formats, of whi ...

(RDF) *

RDF Schema RDF Schema (Resource Description Framework Schema, variously abbreviated as RDFS, , RDF-S, or RDF/S) is a set of classes with certain properties using the RDF extensible knowledge representation data model, providing basic elements for the descr ...

(RDFS) *

SHOE A shoe is an item of footwear intended to protect and comfort the human foot. Though the human foot can adapt to varied terrains and climate conditions, it is vulnerable, and shoes provide protection. Form was originally tied to function, but ...

Controlled natural languages

* Attempto Controlled EnglishKuhn, Tobias.
Attempto Controlled English as ontology language
" REWERSE Annual Meeting. 2006.

Open vocabulary natural languages

* Executable English

Classification by structure (logic type)

Frame-based

Three languages are completely or partially frame-based languages. *

* OKBC * KM

Description logic-based

Description logic Description logics (DL) are a family of formal knowledge representation languages. Many DLs are more expressive than propositional logic but less expressive than first-order logic. In contrast to the latter, the core reasoning problems for DLs are ...

provides an extension of

s, without going so far as to take the leap to

and support for arbitrary predicates. * KL-ONE * RACER *

OWL Owls are birds from the order Strigiformes (), which includes over 200 species of mostly solitary and nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vision, binaural hearing, sharp talons, and feathers a ...

Gellish Gellish is an ontology language for data storage and communication, designed and developed by Andries van Renssen since mid-1990s. It started out as an engineering modeling language ("Generic Engineering Language", giving it the name, "Gellish") b ...

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

and allow general predicates. * Common Logic *

* FO-dot (first-order logic extended with types, arithmetic, aggregates and inductive definitions) * KIF

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 {{Non-classical logic Modeling languages