Questions about owl:Restriction, owl:intersectionOf, and rdfs:subClassOf

I'm a little confused by how to apply multiple owl:Restriction classes to a
class.  For instance, say we have two property restrictions:

<#NeedsResult>
  rdf:type        owl:Restriction             ;
  owl:cardinality "1"^^xsd:nonNegativeInteger ;
  owl:onProperty  <#result>                   .

<#NeedsTime>
  rdf:type        owl:Restriction             ;
  owl:cardinality "1"^^xsd:nonNegativeInteger ;
  owl:onProperty  <#time>                     .

Each of these restrictions says that the class has to have a property present -
namely <#result> or <#time> - correct?  Is it really necessary to specify the
datatypes to be xsd:nonNegativeInteger?

Now say I want to apply those restriction to owl:Class named <#AnApplication>. 
That is, any resource of owl:Class <#AnApplication> has to have the properties
<#result> and <#time> specified.  Would I say:

<#AnApplication>
  rdf:type owl:Class ;
  owl:intersectionOf [
    rdf:type  rdf:List       ;
    rdf:first <#NeedsResult> ;
    rdf:rest  [
      rdf:type  rdf:List     ;
      rdf:first <#NeedsTime> ;
      rdf:rest  rdf:nil      .
    ] .
  ] .

Now in the OWL Guide, it says in section 1.5.2 (example converted to N3):

] Note how completely different this union type 
] construct is from the following.
] 
] <#Fruit>
]   rdf:type        owl:Class        ;
]   rdfs:subClassOf <#SweetFruit>    ;
]   rdfs:subClassOf <#NonSweetFruit> .
] 
] This says that the instances of Fruit are a 
] subset of the intersection of sweet and 
] non-sweet fruit, which we would expect to be 
] the empty set.

Now this confuses me.  Does that mean that the definition of <#AnApplication>
could be written:

<#AnApplication>
  rdf:type        owl:Class      ;
  rdfs:subClassOf <#NeedsResult> ;
  rdfs:subClassOf <#NeedsTime>   .

If not, they why?  I much perfer this shorter form if possible.

Thanks in advance for clearing this up.


--
Jimmy Cerra
https://nemo.dev.java.net


		
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Received on Monday, 4 April 2005 02:25:50 UTC