Ontology
A formal specification of concepts, relationships, and rules within a domain, defining what exists and how things relate in a knowledge domain.
Core Concepts
An ontology is a formal, explicit specification of a shared conceptualization - defining the types, properties, and relationships that exist in a domain with formal semantics enabling automated reasoning.
Example
@prefix ex: <http://example.com/ontology#> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
# Define classes
ex:Person a owl:Class .
ex:Employee a owl:Class ;
rdfs:subClassOf ex:Person .
ex:CEO a owl:Class ;
rdfs:subClassOf ex:Employee .
# Define properties with constraints
ex:worksAt a owl:ObjectProperty ;
rdfs:domain ex:Employee ;
rdfs:range ex:Company .
ex:leadsCompany a owl:ObjectProperty ;
rdfs:domain ex:CEO ;
rdfs:range ex:Company ;
a owl:FunctionalProperty . # CEO leads exactly one company
# Define rules
ex:Employee owl:equivalentClass [
a owl:Restriction ;
owl:onProperty ex:worksAt ;
owl:someValuesFrom ex:Company
] .
See Also
Examples
- •Medical ontology defining diseases, symptoms, treatments and their relationships
- •OWL ontology specifying that 'CEO' is a subclass of 'Employee' with constraint 'leads exactly one Company'