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Re: Difference between cardinality=1 and FunctionalProperty?

From: Roger L. Costello <costello@mitre.org>
Date: Wed, 26 Mar 2003 08:12:47 -0500
Message-ID: <3E81A74F.CF58058D@mitre.org>
To: www-rdf-logic@w3.org
CC: "Costello,Roger L." <costello@mitre.org>

Thanks Peter.  So you are saying that if I defined the Gun class like this:

     <owl:Class rdf:ID="Gun">
          <rdfs:subClassOf>
                <owl:Restriction>
                        <owl:onProperty rdf:resource="#serial"/>
                        <owl:maxCardinality>1</owl:maxCardinality>
                </owl:Restriction>
          </rdfs:subClassOf>
     </owl:Class>

then the two forms would be equivalent?  /Roger


"Peter F. Patel-Schneider" wrote:

> From: "Roger L. Costello" <costello@mitre.org>
> Subject: Difference between cardinality=1 and FunctionalProperty?
> Date: Wed, 26 Mar 2003 06:39:07 -0500
>
> >
> > Hi Folks,
> >
> > Aren't the below two forms essentially stating the same thing:
> >
> >      <owl:Class rdf:ID="Gun">
> >           <rdfs:subClassOf>
> >                 <owl:Restriction>
> >                         <owl:onProperty rdf:resource="#serial"/>
> >                         <owl:cardinality>1</owl:cardinality>
> >                 </owl:Restriction>
> >           </rdfs:subClassOf>
> >      </owl:Class>
> >
> >      <owl:ObjectProperty rdf:ID="serial">
> >            <rdfs:domain rdf:resource="#Gun"/>
> >            <rdfs:range rdf:resource="&rdfs;#Literal"/>
> >      </owl:ObjectProperty>
> >
> > VERSUS
> >
> >      <owl:Class rdf:ID="Gun"/>
> >
> >      <owl:FunctionalProperty rdf:ID="serial">
> >           <rdfs:domain rdf:resource="Gun" />
> >           <rdfs:range  rdf:resource="&rdfs;#Literal"/>
> >      </owl:FunctionalProperty>
> >
> > Both forms state that an instance of Gun must have exactly one value for
> > the serial property; e.g.,
> >
> >      <Gun rdf:ID="SmithWesson">
> >           <serial>ABCD</serial>
> >      </Gun>
> >
> > Correct?  /Roger
> >
>
> Not correct.  Functional properties are only partial functional.  Making
> functional properties be total functional would cause extreme problems.
>
> However, replacing cardinality with maxCardinality above would do the
> trick.
>
> Peter F. Patel-Schneider
> Bell Labs Research
> Lucent Technologies
>
> PS: It would be better to make the range of serial be xsd:string.
Received on Wednesday, 26 March 2003 08:11:56 GMT

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