XML and Semantic Web Technologies. III. Semantic Web / 2. Web Ontology Language (OWL)

Transcription

1 XML and Semantic Web Technologies XML and Semantic Web Technologies. Semantic Web / 2. Web Ontology Language (OWL) Lars Schmidt-Thieme nformation Systems and Machine Learning Lab (SMLL) nstitute of Economics and nformation Systems & nstitute of Computer Science University of Hildesheim Course on XML and Semantic Web Technologies, summer term /42 XML and Semantic Web Technologies. Semantic Web / 2. Web Ontology Language (OWL) 1. Description Logics 2. OWL Basics 3. OWL in RDF 4. OWL XML Syntax Course on XML and Semantic Web Technologies, summer term /42

2 Named ndividuals, Classes, and Roles (1/2) Description logics is a family of special logical calculi that can be represented as subsets of FOL. named individual represents single entity of the domain, e.g., specific persons, cities, etc. denoted by a, b, c,.... corresponds to constants in FOL. interpreted by elements of the domain in models (a ). named concept (aka atomic, primitive; aka class) represents a class of individuals denoted by A, B, C,.... denotes the all class (universe), denotes the empty class. corresponds to unary predicates in FOL. interpreted by sets of elements of the domain in models (A ). Course on XML and Semantic Web Technologies, summer term /42 Named ndividuals, Classes, and Roles (2/2) named role (aka atomic, primitive; aka property) represents a relation between two individuals denoted by R, S, T,.... corresponds to binary predicates in FOL. interpreted by relations between elements of the domain in models (R ). Course on XML and Semantic Web Technologies, summer term /42

3 a : A Statements (1/2) individual a belongs to class A, a is a A. A(a) in FOL. a A in models. charleschaplin: Director goldrush: Movie a, b : R individual a and b are related by R. R(a, b) in FOL. (a, b ) R in models. charleschaplin, goldrush : directs adam, abel : parentof Course on XML and Semantic Web Technologies, summer term /42 A B class A is a subclass of class B. xa(x) B(x) in FOL. A B in models. Statements (2/2) Director Professional Human Movie Artwork A =B abbreviation for A B and B A. Course on XML and Semantic Web Technologies, summer term /42

4 Taxonomies Classes form a taxonomy that can be represented graphically by a directed acyclic graph. individuals can belong to several classes, even if none of them is a subclass of another. example: charleschaplin : Male charleschaplin : Director classes can have several superclasses, even if none of them is a subclass of another (multiple inheritance). example: Actrice : Female Actrice : Professional subclasses have not to be exhaustive, interior nodes have not to be abstract, but can contain individuals that belong to none of the subclasses. example: there are female professionals that are not actrices (e.g., directors). Course on XML and Semantic Web Technologies, summer term /42 Class constructors: Boolean expressions (1/2) New classes can be constructed, e.g., from boolean expressions of existing classes. These new classes then can be used in statements wherever named classes can be used. A B class of individuals belonging to both classes A and B. A(x) B(x) in FOL. A B in models. CityState =Country City luxemburg : CityState A B class of individuals belonging to at least one of the classes A or B. A(x) B(x) in FOL. A B in models. Parents =Father Mother Course on XML and Semantic Web Technologies, summer term /42

5 Class constructors: Boolean expressions (1/2) A class of individuals not belonging to class A. A(x) in FOL. \ A in models. Female =Human Male Course on XML and Semantic Web Technologies, summer term /42 Class constructors: exists restriction (1/2) Furthermore, classes can be constructed from roles by posing constraints on the related individuals (restrictions). R unqualified exists restriction class of individuals that are related to at least one other individual by relation R. yr(x, y) in FOL. {x y : (x, y) R } in models. Parents = ParentOf Course on XML and Semantic Web Technologies, summer term /42

6 R.A qualified exists restriction Class constructors: exists restriction (2/2) class of individuals that are related to at least one individual of class A by relation R. ya(y) R(x, y) in FOL. {x y A : (x, y) R } in models. ParentsOfASon = ParentOf.Male R. could be used to express an unqualified exists expression. Course on XML and Semantic Web Technologies, summer term /42 R.A value restriction (always qualified) Class constructors: value restriction class of individuals that are related only to individuals of class A by relation R. yr(x, y) A(y) in FOL. {x y : (x, y) R y A } in models. HappyParents = ParentOf.Happy All qualified restrictions could be nested, e.g., Grandparents = ParentOf. ParentOf. Course on XML and Semantic Web Technologies, summer term /42

7 A simple description logic calculus: FL FL class constructors: symbol name formal semantics A atomic / primitive concept C R atomic / primitive role R C D conjoined concept, and C D R exists restriction, some {x y : (x, y) R } R.C value restriction, all {x y : (x, y) R y C } FL statements: C D subsumption, axiom C D C =D concept equality / definition C = D a : C concept assertion a C a, b : R role assertion (a, b ) R concept = class, set of individuals. role = relation between pairs of individuals. Course on XML and Semantic Web Technologies, summer term /42 ALC ALC class constructors: symbol name formal semantics A atomic / primitive concept C R atomic / primitive role R top, all class bottom, empty class C complement, not \ C C D conjunction, and C D C D disjunction, or C D R.C exists restriction, some {x y C : (x, y) R } R.C value restriction, all {x y : (x, y) R y C } ALC statements: C D subsumption, axiom C D C =D concept equality / definition C = D a : C concept assertion a C a, b : R role assertion (a, b ) R Course on XML and Semantic Web Technologies, summer term /42

8 ALC example Formalize the concept of DNK = "double income, no kids". atomic concepts: Human, Employed. atomic roles: partnerof, parentof. Employed Human DNK = Employed partnerof.employed parentof.human Course on XML and Semantic Web Technologies, summer term /42 Class constructors: functional number restrictions 1R functional number restriction class of individuals that are related to at most one individual by relation R. y, z : R(x, y) R(x, z) y = z in FOL. {x #{y (x, y) R } 1} in models. Monogamous = 1MarriedTo 2R functional number restriction class of individuals that are related to at least two individuals by relation R. y, z : R(x, y) R(x, z) y z in FOL. {x #{y (x, y) R } 2} in models. Polygamous = 2MarriedTo Do not confuse number restrictions with numeric properties (i.e., age of a person) or restrictions on numeric properties (i.e., a baby is a human of age at most 1 year). Course on XML and Semantic Web Technologies, summer term /42

9 Class constructors: (general) number restrictions nr number restriction (with n a natural number). class of individuals that are related to at most n individuals by relation R. y 1, y 2,..., y n, y n+1 : R(x, y 1 ) R(x, y 2 )... R(x, y n+1 ) (y 1 = y 2 y 1 = y 3... y n = y n+1 ) in FOL. {x #{y (x, y) R } n} in models. MiniGroup = 5HasMember nr number restriction (with n a natural number). class of individuals that are related to at least n individuals by relation R. y 1, y 2,..., y n : R(x, y 1 ) R(x, y 2 )... R(x, y n ) y 1 y 2 y 1 y 3... y n 1 y n in FOL. {x #{y (x, y) R } n} in models. OverBookedAirbus380 = 556HasBooking Course on XML and Semantic Web Technologies, summer term /42 Class constructors: qualified number restrictions nr.a qualified number restriction (with n a natural number). class of individuals that are related to at most n individuals of class A by relation R. y 1, y 2,..., y n, y n+1 : A(y 1 ) A(y 2 )... A(y n+1 ) R(x, y 1 ) R(x, y 2 )... R(x, y n+1 ) (y 1 = y 2 y 1 = y 3... y n = y n+1 ) in FOL. {x #{y (x, y) R } n} in models. MiniGroup = 5HasMember.Adult nr.a qualified number restriction (with n a natural number). class of individuals that are related to at least n individuals of class A by relation R. y 1, y 2,..., y n : A(y 1 ) A(y 2 )... A(y n ) R(x, y 1 ) R(x, y 2 )... R(x, y n ) y 1 y 2 y 1 y 3... y n 1 y n in FOL. {x #{y (x, y) R } n} in models. LargeFamily = 3HasMember.Child Course on XML and Semantic Web Technologies, summer term /42

10 Class constructors: nominal, enumeration {o} nominal class that contains exactly individual o. x = o in FOL. {o} in models. CharlesChaplin ={charleschaplin} Enumerations can be formed by unions of nominals: {o 1,..., o n } = {o 1 } {o 2 }... {o n } example: GreatDirectors ={charleschaplin, friedrichmurnau, fritzlang} Course on XML and Semantic Web Technologies, summer term /42 ALC extensions / class constructors class constructors of ALC extensions: symbol name formal semantics 1R functional number (F) {x #{y (x, y) R } 1} 2R restrictions {x #{y (x, y) R } 2} nr number restrictions, (N) {x #{y (x, y) R } n} nr cardinality {x #{y (x, y) R } n} nr.c qual. cardinality (Q) {x #{y C (x, y) R } n} nr.c {x #{y C (x, y) R } n} {o} nominal, (O) {o } {o 1,..., o n } enumeration, one-of {o 1,..., o n} Obviously, (Q) (N) (F). Course on XML and Semantic Web Technologies, summer term /42

11 Role constructors: Boolean expressions (1/2) R S role conjunction role that relates x to y iff both R and S do. R(x, y) S(x, y) in FOL. R S in models. ncestousperson = smarriedto ssiblingof R S role disjunction role that relates x to y iff R or S does. R(x, y) S(x, y) in FOL. R S in models. Parents = HasSon HasDaughter ParentOfSingleChild = 1HasSon HasDaughter Course on XML and Semantic Web Technologies, summer term /42 R role negation Role constructors: Boolean expressions (2/2) role that relates x to y iff R does not. R(x, y) in FOL. \ R in models. Philanthropists = Likes Do not confuse role negation with inverse roles (see next slide). Course on XML and Semantic Web Technologies, summer term /42

12 R inverse role Role constructors: inverse role that relates x to y exactly if R relates y to x. R(y, x) in FOL. {(y, x) (x, y) R } in models. haschild =hasparent Course on XML and Semantic Web Technologies, summer term /42 R S role composition Role constructors: composition role that relates x to y iff there exists a z s.t. x is related to z by R and z related to y by S. zr(x, z) S(z, y) in FOL. {(x, y) z : (x, z) R (z, y) S } in models. OnlyChild = 1HasParent HasParent Course on XML and Semantic Web Technologies, summer term /42

13 Role statements: subsroles R S subrole whenever two instances are related by R, they are also related by S. subroles are used to build role hierarchies R(x, y) S(x, y) in FOL. R S in models. ismother isparent R =S role equivalence, abbreviation for R S and S R. Course on XML and Semantic Web Technologies, summer term /42 Role statements: transitive roles R R + transitive role whenever x and y as well as y and z are related by R, then x and z are also related by R directly R(x, y) R(y, z) R(x, z) in FOL. R = (R ) + in models where for any relation R S S on any set S R + := tr n (R) n N tr(r) := {(x, y) z S : (x, z), (z, y) R} sancestorof R + (Anne, Bert) : smotherof (Bert, Clara) : sfatherof sfatherof, ismotherof sancestorof Anne, Clara : sancestorof Course on XML and Semantic Web Technologies, summer term /42

14 ALC extensions / role constructors role constructors of ALC extensions: symbol name formal semantics R atomic / primitive role R R inverse () {(y, x) (x, y) R } R complement, not \ R R Q conjunction, and R Q R Q disjunction, or R Q R Q composition {(x, y) z : (x, z) R (z, y) Q statements of ALC extensions: R Q role hierarchy (H) R Q R =Q role equality / definition R = Q R R + transitive role ( R +) R = (R ) + where for any relation R S S on any set S R + := tr n (R) n N tr(r) := {(x, y) z S : (x, z), (z, y) R} Course on XML and Semantic Web Technologies, summer term /42 SH := ALCH R + ALC extensions / SH-logics n SH, number restrictions (Q),(N),(F) may only be applied to simple roles, i.e., roles that neither are transitive nor have transitive subroles. SHN + (where N + := (N) for arbitrary roles) is already undecidable. Course on XML and Semantic Web Technologies, summer term /42

15 Additional syntactic symbols: datatypes d D, concrete primitive roles R R D. ALC extensions / Datatypes Additional model components: set D values, as domain of all datatype for each d D a set d datatype values, symbol name formal semantics R abstract primitive role R A R R concrete primitive role R D (D) R D d datatype d D d datatype negation D \ d D of for each concrete primitive role R R D a set R D. Datatypes may be used wherever concepts are used (e.g., in exists and value restrictions, number restrictions etc.). Role hierarchies for abstract and concrete roles are disjunct (i.e., in R Q both R and Q are in R A or R D ). Transitivity can only be declared for abstract roles. Course on XML and Semantic Web Technologies, summer term /42 FOL, F Logics SHOQ SHON(D) = OWL DL undecidable SHQ SHON SHF(D) = OWL Lite NExpTime SHF ExpTime SQ S S := ALCR+ ALC PSpace Figure 1: Complexity of satisfiability and subsumption of different description logics. Course on XML and Semantic Web Technologies, summer term /42

16 XML and Semantic Web Technologies. Semantic Web / 2. Web Ontology Language (OWL) 1. Description Logics 2. OWL Basics 3. OWL in RDF 4. OWL XML Syntax Course on XML and Semantic Web Technologies, summer term /42 XML and Semantic Web Technologies / 2. OWL Basics OWL Specification The OWL specification consists of the following parts: OWL Web Ontology Language Overview (REC-2004/02/10), OWL Web Ontology Language Guide (REC-2004/02/10) an example, OWL Web Ontology Language Reference (REC-2004/02/10), OWL Web Ontology Language Semantics and Abstract Syntax (REC-2004/02/10), OWL Web Ontology Language XML Presentation Syntax (REC-2004/02/10) as well as further documents on test cases and use cases and requirements. OWL is an RDF vocabulary extension (i.e., it adds resources with defined formal semantics). The OWL namespace is Course on XML and Semantic Web Technologies, summer term /42

17 XML and Semantic Web Technologies / 2. OWL Basics Three Language Levels OWL Lite OWL DL (Description Logics) OWL Full Each OWL Lite document is an OWL DL document, each OWL DL document an OWL Full document. Each OWL Lite inference is an OWL DL inference, each OWL DL inference an OWL Full inference. Course on XML and Semantic Web Technologies, summer term /42 XML and Semantic Web Technologies / 2. OWL Basics Abstract Syntax (1/2) Abstract Syntax DL Syntax Semantics Descriptions (C) A (UR reference) A A owl:thing owl:thing = owl:nothing owl:nothing = {} intersectionof(c 1 C 2...) C 1 C 2 (C 1 D 1) = C1 D2 unionof(c 1 C 2...) C 1 C 2 (C 1 C 2) = C1 C2 complementof(c) C ( C) = \ C oneof(o 1...) {o 1,...} {o 1,...} = {o 1,...} restriction(r somevaluesfrom(c)) R.C ( R.C) = {x y. x, y R and y C } restriction(r allvaluesfrom(c)) R.C ( R.C) = {x y. x, y R y C } restriction(r hasvalue(o)) R : o ( R.o) = {x x, o R } restriction(r mincardinality(n)) n R ( n R) = {x ({y. x, y R }) n} restriction(r mincardinality(n)) n R ( n R) = {x ({y. x, y R }) n} restriction(u somevaluesfrom(d)) U.D ( U.D) = {x y. x, y U and y D D } restriction(u allvaluesfrom(d)) U.D ( U.D) = {x y. x, y U y D D } restriction(u hasvalue(v)) U : v (U : v) = {x x, v U } restriction(u mincardinality(n)) n U ( n U) = {x ({y. x, y U }) n} restriction(u maxcardinality(n)) n U ( n U) = {x ({y. x, y U }) n} Data Ranges (D) D (UR reference) D D D D oneof(v 1...) {v 1,...} {v 1,...} = {v1,...} Object Properties (R) R (UR reference) R R R (R ) = (R ) Datatype Properties (U) U (UR reference) U U D ndividuals (o) o (UR reference) o o Data Values (v) v (RDF literal) v v = v D Fig. 1. OWL DL Descriptions, Data Ranges, Properties, ndivdiuals, and Data Values Figure 2: Abstract OWL-DL syntax (1/2; Horrocks2003). Course on XML and Semantic Web Technologies, summer term /42

18 XML and Semantic Web Technologies / 2. OWL Basics Abstract Syntax (2/2) Abstract Syntax DL Syntax Semantics Class(A partial C 1...C n) A C 1... C n A C1... Cn Class(A complete C 1...C n) A = C 1... C n A = C1... Cn EnumeratedClass(A o 1...o n) A = {o 1,..., o n} A = {o 1,..., o n} SubClassOf(C 1 C 2) C 1 C 2 C1 C2 EquivalentClasses(C 1...C n) C 1 =... = C n C1 =... = Cn DisjointClasses(C 1...C n) C i C j =, i j Ci Cj {}, i j Datatype(D) D D DatatypeProperty(U super(u 1)...super(U n) U U i U Ui domain(c 1)...domain(C m) 1 U C i U Ci D range(d 1)...range(D l) U.D i U Di [Functional]) 1 U U is functional SubPropertyOf(U 1 U 2) U 1 U 2 U1 U2 EquivalentProperties(U 1...U n) U 1 =... = U n U1 =... = Un ObjectProperty(R super(r 1)...super(R n) R R i R Ri domain(c 1)...domain(C m) 1 R C i R Ci range(c 1)...range(C l) R.C i R Ci [inverseof(r 0] R = ( R 0) R = (R0 ) [Symmetric] R = ( R) R = (R ) [Functional] 1 R R is functional [nversefunctional] 1 R (R ) is functional [Transitive]) T r(r) R = (R ) + SubPropertyOf(R 1 R 2) R 1 R 2 R1 R2 EquivalentProperties(R 1...R n) R 1 =... = R n R1 =... = Rn AnnotationProperty(S) ndividual(o type(c 1)...type(C n) o C i o Ci value(r 1 o 1)...value(R n o n) o, o i R i o, o i Ri value(u 1 v 1)...value(U n v n)) o, v i U i o, vi Ui Samendividual(o 1...o n) o 1 =... = o n o i = o j Differentndividuals(o 1...o n) o i o j, i j o i o j, i j Fig. 2. OWL DL Axioms and Facts Figure 3: Abstract OWL-DL syntax (2/2; Horrocks2003). Course on XML and Semantic Web Technologies, summer term /42 XML and Semantic Web Technologies / 2. OWL Basics Example / OWL/abstract DL syntax 1 Class( Human complete ) 2 Class( Employed complete ) 3 ObjectProperty( partnerof ) 4 ObjectProperty( parentof ) SubClassOf( Employed Human ) 7 8 Class( DNK complete 9 Employed 10 restriction( partnerof somevaluesfrom( Employed ) ) 11 complementof( restriction ( parentof somevaluesfrom ( Human ) ) ) 12 ) Figure 4: DNK concept in OWL/abstract DL syntax. Course on XML and Semantic Web Technologies, summer term /42

19 XML and Semantic Web Technologies. Semantic Web / 2. Web Ontology Language (OWL) 1. Description Logics 2. OWL Basics 3. OWL in RDF 4. OWL XML Syntax Course on XML and Semantic Web Technologies, summer term /42 XML and Semantic Web Technologies / 3. OWL in RDF OWL Class Hierarchy rdfs:resource instance of / rdf:type is a / rdfs:subclassof rdfs:class rdf:property rdfs:container rdf:list rdfs:datatype owl:class owl:object Property owl:datatype Property owl:functional Property owl:thing owl:restriction owl:alldifferent owl:nothing owl:nverse FunctionalProperty owl:transitive Property owl:symmetric Property Figure 5: OWL Class Hierarchy. Course on XML and Semantic Web Technologies, summer term /42

20 XML and Semantic Web Technologies / 3. OWL in RDF for class descriptions: OWL RDF Vocabulary (1/2) owl:oneof (owl:class, rdf:list), owl:onproperty (owl:restriction, rdf:property), owl:allvaluesfrom (owl:restriction, owl:class rdfs:datatype), etc. owl:intersectionof (owl:class, rdf:list), owl:unionof (owl:class, rdf:list), owl:complementof (owl:class, owl:class), for class axioms: rdfs:subclassof (owl:class, owl:class), owl:equivalentclass (owl:class, owl:class), owl:disjointwith (owl:class, owl:class), Course on XML and Semantic Web Technologies, summer term /42 XML and Semantic Web Technologies / 3. OWL in RDF OWL RDF Vocabulary (2/2) for role / property descriptions and axioms: rdfs:subpropertyof (rdf:property, rdf:property), rdfs:domain (rdf:property, rdfs:class), rdfs:range (rdf:property, rdfs:class), owl:equivalentproperty (rdf:property, rdf:property) owl:inverseof (owl:objectproperty, owl:objectproperty), for individual axioms: owl:sameas (ndividual, ndividual), owl:differentfrom (ndividual, ndividual), owl:distinctmembers (owl:alldifferent, rdf:list), for datatypes: owl:oneof (rdfs:datarange, rdf:list) Course on XML and Semantic Web Technologies, summer term /42

21 XML and Semantic Web Technologies / 3. OWL in RDF RDF Schema Features: Class (Thing, Nothing) rdfs:subclassof intersectionof allvaluesfrom applied to class names only applied to class names only somevaluesfrom rdf:property DL unionof DL hasvalue rdfs:subpropertyof DL complementof Cardinality: rdfs:domain rdfs:range Boolean Combinations of Class Expressions: Class Axioms: DL oneof, datarange Restriction onproperty mincardinality only 0 or 1 ndividual (n)equality: Property Characteristics: ObjectProperty maxcardinality only 0 or 1 equivalentclass cardinality DatatypeProperty applied to class names only only 0 or 1 inverseof equivalentproperty (red: completely forbidden TransitiveProperty in OWL Lite; green: restricted in OWL Lite) DL disjointwith SymmetricProperty sameas Datatypes differentfrom FunctionalProperty xsd datatypes AllDifferent, nversefunctionalproperty Header nformation: distinct- Members Property Restrictions: Ontology imports Versioning: versionnfo priorversion backwardcompatiblewith incompatiblewith DeprecatedClass DeprecatedProperty Annotation Properties: rdfs:label rdfs:comment rdfs:seealso rdfs:isdefinedby AnnotationProperty OntologyProperty Course on XML and Semantic Web Technologies, summer term /42 XML and Semantic Web Technologies / 3. OWL in RDF Example / OWL/RDF/N3 1@prefix rdf: < 2@prefix rdfs: < 3@prefix owl: < 4@prefix : <#>. 5 6:Human rdf:type owl:class. 7:Employed rdf:type owl:class. 8:partnerOf rdf:type owl:objectproperty. 9:parentOf rdf:type owl:objectproperty. 10:Employed rdfs:subclassof :Human :DNK rdf:type owl:class ; 13 owl:intersectionof ( :Employed 14 [ rdf:type owl:restriction ; 15 owl:onproperty :partnerof ; owl:somevaluesfrom :Employed ] 16 [ owl:complementof 17 [ rdf:type owl:restriction ; 18 owl:onproperty :parentof ; owl:somevaluesfrom :Human ]] 19 ). Figure 6: DNK concept in OWL/RDF/N3. Course on XML and Semantic Web Technologies, summer term /42

22 XML and Semantic Web Technologies / 3. OWL in RDF Example / OWL/RDF/XML 12 <owl:class rdf:about="#human"/> 13 <owl:class rdf:about="#employed"> 14 <rdfs:subclassof rdf:resource="#human"/> 15 </owl:class> 16 <owl:objectproperty rdf:about="#parentof"/> 17 <owl:objectproperty rdf:about="#partnerof"/> 18 <owl:class rdf:about="#dnk"> 19 <owl:intersectionof rdf:parsetype="collection"> 20 <Employed/> 21 <owl:restriction> 22 <owl:onproperty rdf:resource="#partnerof"/> 23 <owl:somevaluesfrom rdf:resource="#employed"/></owl:restriction> 24 <owl:complementof> 25 <owl:restriction> 26 <owl:onproperty rdf:resource="#parentof"/> 27 <owl:somevaluesfrom rdf:resource="#human"/></owl:restriction> 28 </owl:complementof> 29 </owl:intersectionof> 30 </owl:class> Figure 7: DNK concept in OWL/RDF/XML (excerpt). Course on XML and Semantic Web Technologies, summer term /42 XML and Semantic Web Technologies. Semantic Web / 2. Web Ontology Language (OWL) 1. Description Logics 2. OWL Basics 3. OWL in RDF 4. OWL XML Syntax Course on XML and Semantic Web Technologies, summer term /42

23 XML and Semantic Web Technologies / 4. OWL XML Syntax OWL Abstract Syntax (for OWL-DL), OWL Syntaxes all kinds of RDF syntaxes: OWL/RDF/N3, OWL/RDF/XML, etc. OWL/XML syntax. Course on XML and Semantic Web Technologies, summer term /42 XML and Semantic Web Technologies / 4. OWL XML Syntax OWL/XML 3 schemata, one for each language level: OWL Lite (owl1-lite.xsd), OWL DL (owl1-dl.xsd), and OWL Full (owl1-full.xsd). namespace (usual prefix owlx) Please see OWL Web Ontology Language XML Presentation Syntax (REC-2004/02/10) for syntax details (not covered here explicitly due to time restrictions). Course on XML and Semantic Web Technologies, summer term /42

24 XML and Semantic Web Technologies / 4. OWL XML Syntax 1 <?xml version="1.0"?> 2 <owlx:ontology xmlns:owlx=" 3 name=" 4 <owlx:class owlx:name="human" owlx:complete="true"/> 5 <owlx:class owlx:name="employed" owlx:complete="false"> 6 <owlx:class owlx:name="human"/> 7 </owlx:class> 8 <owlx:objectproperty owlx:name="parentof"/> 9 <owlx:objectproperty owlx:name="partnerof"/> 10 <owlx:class owlx:name="dnk"> 11 <owlx:intersectionof> 12 <owlx:class name="employed"/> 13 <owlx:objectrestriction owlx:property="#partnerof"> 14 <owlx:somevaluesfrom owlx:class="employed"/></owlx:objectrestriction> 15 <owlx:complementof> 16 <owlx:objectrestriction owlx:property="#parentof"> 17 <owlx:somevaluesfrom owlx:class="human"/></owlx:objectrestriction> 18 </owlx:complementof> 19 </owlx:intersectionof> 20 </owlx:class> 21 </owlx:ontology> Figure 8: DNK concept in OWL/XML. Course on XML and Semantic Web Technologies, summer term /42