Meaning of OWL axiom in Turtle syntax?

Question

I have the turtle statement:

:Parent rdf:type owl:Class ;

    owl:equivalentClass ;
        rdf:type owl:Class ;
        owl: unionOf (
                [   rdf:type owl:Restriction ;
                    owl:onProperty :fatherOf ;
                    owl:someValuesFrom :Person
                ]
                [   rdf:type owl:Restriction ;
                    owl:onProperty :motherOf ;
                    owl:someValuesFrom :Person
                ]
        }
    ].

Could someone explain to me the concept of Parent within this statement. Would it also be possible for someone to be a mother or father of a person without being a parent?

Answer 1

Could someone explain to me the concept of Parent within this statement.

Note that Turtle is just a serialization format for RDF. In RDF , :Parent is an IRI (we'd need to know what the prefix : stands for in order to know exactly what it is), and it's the subject of at least one RDF triple:

:Parent rdf:type owl:Class .

The "Turtle" snippet that you're showing isn't actually legal Turtle. If you look at the brackets, you'll see that they're mismatched, and there's a } in there too, which has no place in a Turtle document. Then there's a part

 :Parent rdf:type owl:Class ; owl:equivalentClass ; 

which isn't right either. The Turtle syntax allows you to abbreviate the two triples

:A :p :B .
:A :q :C .

as

:A :p :B ;
   :q :C .

but in your snippet there's an object missing after owl:equivalentClass . See Meaning of SPARQL operator ';' for more information about this syntax.

Based on the rest of the content, though, I'm guessing that you're trying to look at the OWL axiom:

Parent ≡ ∃ fatherOf.Person ⊔ ∃ motherOf.Person

which could also be written in the Manchester syntax as

Parent equivalentClass ((fatherOf some Person) or (motherOf some Person))

That last representation might make it clearer what the axiom is expression. The expression (fatherOf some Person) is the class of all individuals that are related to some Person by the property fatherOf , ie, all the individuals that are the father of some person. Similarly, (motherOf some Person) is the class of individuals that are the mother of some person. If you take the union of these, then you have the class of all individuals that are the father of some person or the mother of some person. The axiom as a whole says that that class is equivalent to class Parent . That is, the class Parent is exactly the class of individuals that are fathers or mothers of some person.

Would it also be possible for someone to be a mother or father of a person without being a parent?

No. If an individual is the father (mother) of a person, then they are a member of (fatherOf some Person) ( (motherOf some Person) ), and thus are a member of ((fatherOf some Person) or (motherOf some Person)) , and since that class is equivalent to Parent , then that individual is a member of Parent .