owl 2.0 primer part01

OWL 2.0 Primer

Classes, Properties, and Individuals

OWL 2.0 2

Contents

• Basic Notions• Classes, Properties, Individuals & basic mod-

eling with them

OWL 2.0 3

Basic Notions

• OWL2 is a knowledge representation lan-guage.Axioms: the basic statements that an OWL ontology ex-presses.

Entities: elements used to refer to real-world objects.

Expressions: combinations of entities to form complex de-scriptions from basic ones

OWL 2.0 4

1. Mary and John are married.2. Mary is female.

Axioms

individu-als

properties

classes

Entities

Mary, John

married

female

Expressions

Entity Entity+

Female professor

female professor+

5

Classes and Instances(Individuals)

Functional-Style Syntax RDF-XML Syntax

ClassAssertion( :Person :Mary)

<owl:Class rdf:ID=“Person”/>

1.<owl:Thing rdf:ID=“Mary”/><owl:Thing rdf:about=“Mary”> <rdf:type rdf:resource=“#Person”></owl:Thing>

2.<Person rdf:ID=“Mary”/>

OWL 2.0

An individual named Mary and states this individual is a person

OWL 2.0 6

Class Hierarchies


SubClassOf( :Mother :Woman)

<owl:Class rdf:ID=“Woman”/>

<owl:Class rdf:ID=“Mother”> <rdfs:subClassOf rdf:resource=“#Woman”/></owl:Class>

Every individual which is specified as an instance of the class Woman is also an in-stance of the class Person as well.

OWL 2.0 7

Class Hierarchies


EquivalentClasses( :Person :Human )

<owl:Class rdf:ID=“Human”/>

<owl:Class rdf:ID=“Person”> <owl:equivalentClass rdf:resource=“#Human”/></owl:Class>

Every instance of the class Person is also an instance of class Human, and vice versa.

OWL 2.0 8

Class Disjointness


DisjointClasses( :Woman :Man)

<owl:Class rdf:ID=“Man”/>

<owl:Class rdf:ID=“Woman”> <owl:disjointWith rdf:resource=“#Man”/></owl:Class>

Incompatibility relationship between class of Woman and Man.

OWL 2.0 9

Object Properties


ObjectPropertyAssertion( :hasWife :John :Mary)

<Person rdf:ID=“Mary”/>

<Person rdf:ID=“John”> <hasWife rdf:resource=“#Mary”/></Person>

Mary is John’s wife

John MaryhasWife

OWL 2.0 10

Property Hierarchies


SubObjectPropertyOf( :hasWife :hasSpouse )

<owl:ObjectProperty rdf:ID=“hasWife”> <rdfs:subPropertyOf rdf:resource=“#hasSpouse”/> … …</owl:ObjectProperty>

Whenever B is known to be A’s wife, it is also known to be A’s spouse.

OWL 2.0 11

Domain and Range Restrictions


ObjectPropertyDomain( :hasWife :Man )ObjectPropertyRange( :hasWife :Woman )

<owl:Class rdf:ID=“Man”/><owl:Class rdf:ID=“Woman”/>

<owl:ObjectProperty rdf:ID=“hasWife”> <rdfs:domain rdf:resource=“#Man”/> <rdfs:range rdf:resource=“#Woman”/></owl:ObjectProperty>

B is the wife of A obviously implies that B is a woman and A is a man.

OWL 2.0 12

Equality and Inequality of Individuals


1.DifferentIndividuals( :John :Bill ) <Man rdf:ID=“John”> <owl:differentFrom rdf:resource=“#Bill”/></Man>

2.SameIndividual( :James :Jim ) <Man rdf:ID=“James”> <owl:sameAs rdf:resource=“#Jim”/></Man>

John and Bill are not the same individuals.James and Jim are the same individuals.

OWL 2.0 13

Datatypes


DataPropertyAssertion( :hasAge :John “51”^^xsd:integer )

<Man rdf:ID=“John”> <hasAge rdf:datatype=“&xsd;integer”>51</hasAge></Man>

John’s age is 51

OWL 2.0 14

Domain and range of Datatypes


DataPropertyDomain( :hasAge :Person )DataPropertyRange( :hasAge xsd:nonNegativeInteger )

<owl:DatatypeProperty rdf:ID=“hasAge”> <rdfs:domain rdf:resource=“Person”/> <rdfs:range rdf:resource=“&xsd;nonNegativeInteger”/></owl:DatatypeProperty>

Domain and range of datatypeproperty

OWL 2.0 15

Protégé 3.4.4 Protégé 4.1 beta

OWL 2.0 16

Q&A

owl 2.0 primer part01

Education