rdfowlset-intersectionset-union

OWL intersection vs union

Given the following triples, are the domain and range a union or intersection or something else?

<http://www.stackoverflow.com/questions/ask> rdfs:domain <http://stackoverflow.com/questions/tagged/rdf> .
<http://www.stackoverflow.com/questions/ask> rdfs:domain <http://stackoverflow.com/questions/tagged/owl> .
<http://www.stackoverflow.com/questions/ask> rdfs:domain <https://www.w3.org/TR/owl-ref/#Boolean> .
<http://www.stackoverflow.com/questions/ask> rdfs:range <http://stackoverflow.com/questions/tagged/rdf> .
<http://www.stackoverflow.com/questions/ask> rdfs:range <http://stackoverflow.com/questions/tagged/owl> .
<http://www.stackoverflow.com/questions/ask> rdfs:range <https://www.w3.org/TR/owl-ref/#Boolean> .


In other words, does the http://www.stackoverflow.com/questions/ask predicate have three domains, three ranges, and any domain-range pairing is valid can be inferred?

Edit: The w3.org documentation for domain and range states:

Where a property P has more than one rdfs:domain property, then the resources denoted by subjects of triples with predicate P are instances of all the classes stated by the rdfs:domain properties.

Where P has more than one rdfs:range property, then the resources denoted by the objects of triples with predicate P are instances of all the classes stated by the rdfs:range properties.

Solution

  • You can think of it as intersection, but it's a little bit indirect. When you have a triple

    p rdfs:domain C

    it means that whenever you have a triple

    a p b

    you can infer that

    a rdf:type C

    So, when you have

    p rdfs:domain C
    p rdfs:domain D
    p rdfs:domain E

    a p b

    you can infer

    a rdf:type C
    a rdf:type D
    a rdf:type E

    which is the effect of having declared

    p rdfs:domain (C ⊓ D ⊓ E)

    Similarly, from p rdfs:range F and a p b we can infer b rdf:type F.

    That means that we can answer your final question:

    In other words, does the http://www.stackoverflow.com/questions/ask predicate have three domains, three ranges, and any domain-range pairing is valid?

    OWL isn't about specifying what's "valid" or not in this regard, it's about specifying what you can infer from other data. If you have:

    p rdfs:domain A
    p rdfs:domain B
    p rdfs:domain C

    p rdfs:range D
    p rdfs:range E
    p rdfs:range F

    then from

    a p b

    you'll be able to infer

    a rdf:type A
    a rdf:type B
    a rdf:type C

    b rdf:type D
    b rdf:type E
    b rdf:type F