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RE: Correct Owl representation

From: <Deepali.Khushraj@nokia.com>
Date: Fri, 26 Sep 2003 20:07:45 -0400
Message-ID: <DC504E9C3384054C8506D3E6BB01246001753707@bsebe001.americas.nokia.com>
To: <www-rdf-interest@w3.org>

I wonder if it has something to do with datatype properties in OWL being specified as functional. So if focal-length is defined to have datatype xsd:string, then using focal-length as xsd:normalizedString (or xsd:token) could be valid. Unless we explicitly specify this information the parser has no way to figure it out.

<owl:DatatypeProperty rdf:ID="focal-length">
        <owl:equivalentProperty rdf:resource="#size"/>
        <rdfs:domain rdf:resource="#Lens"/>
        <rdfs:range rdf:resource="&xsd;#string"/>

   <focal-length rdfs:datatype="&xsd;normalizedString">75-300mm zoom</focal-length>
   <f-stop rdfs:datatype="&xsd;normalizedString">4.5-5.6</f-stop>

I am not sure if this is a valid thing to do.


*DISCLAIMER*: This is a wild guess.

-----Original Message-----
From: ext Benjamin Nowack [mailto:office@e-senses.de]
Sent: Friday, September 26, 2003 6:31 PM
To: Monika Solanki
Cc: www-rdf-interest
Subject: Re: Correct Owl representation

Monika Solanki (monika@dmu.ac.uk) schrieb am 26.09.2003:
>    <focal-length>75-300mm zoom</focal-length>
>   <f-stop>4.5-5.6</f-stop>
>Would the above be incorrect representation in OWL ?
>Would it be correct to do it like this  
>    <focal-length rdf:datatype="&xsd;string">75-300mm zoom</focal-length>
>   <f-stop rdf:datatype="&xsd;string">4.5-5.6</f-stop>
>If this is correct, then what is the rationale behind specifying range 
>as "String" in defining the property ?

you are right. properties of individuals always need the additional
datatype when serialized as RDF/XML (section 6.1 of [1]). I think the 
reason is the "RDF/XML" format. You can define the range at the ontology 
level, but this is separate from the instance level as the rdf:datatype
attribute seems to be required if you want to write _typed_ literals
(section 2.9 of [2]). I'm not sure but this could be the reason for the
redundancy, just to make sure that rdf parsers don't handle the property
values as plain literals.

hope that helps..


[1] http://www.w3.org/TR/owl-ref/
[2] http://www.w3.org/TR/rdf-syntax-grammar/

benjamin nowack

am exerzierplatz 1
de-97072 wuerzburg
Received on Friday, 26 September 2003 20:08:38 UTC

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