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Re: owl:hasValue range?

From: Jeff Z. Pan <pan@cs.man.ac.uk>
Date: Fri, 21 May 2004 23:42:39 +0100
Message-ID: <00de01c43f84$fd8f33b0$6bc65882@cs.man.ac.uk>
To: "Dan Brickley" <danbri@w3.org>, "Benjamin Nowack" <bnowack@appmosphere.com>
Cc: <www-rdf-logic@w3.org>


On May 18, 2004 11:40 AM, Benjamin Nowack wrote:
>
>On 17.05.2004 19:41:26, Dan Brickley wrote:
>>
>><owl:Restriction>
>  <owl:onProperty rdf:resource="#hasParent" />
>  <owl:hasValue rdf:resource="#Clinton" />
></owl:Restriction>
>
>><owl:Restriction>
>  <owl:onProperty rdf:resource="#hasParentName" />
>  <owl:hasValue>Bill Clinton</owl:hasValue>
></owl:Restriction>
>
>seems fine to me. you may add datatype information for a
more precise description,

Indeed.

>although it may be sufficient
to have it in the property and range definition, e.g.:

><owl:Restriction>
  <owl:onProperty rdf:resource="#hasParentName" />
  <owl:hasValue rdf:datatype="&xsd;string">Bill Clinton</owl:hasValue>
</owl:Restriction>

>and/or

><owl:DatatypeProperty rdf:ID="hasParentName">
  <rdfs:domain rdf:resource="#Person"/>
  <rdfs:range rdf:resource="&xsd;string"/>
</owl:DatatypeProperty>

>a related NOTE in the ref doc says
[[
for datatypes "semantically equal" means that the lexical
representation of the literals maps to the same value
]]

I would suggest a quick check of the Semantics and Abstract Syntax document, whenever
something formally and explicitly defined is needed.

>I don't know, if something like

>"1.0"^^xsd:float
is "semantically equal" to
"1.0"^^xsd:string

No. As "1.0"^^xsd:float is mapped to a float while "1.0"^^xsd:string is mapped to a
string.

>or, in the example above, if

>"Bill Clinton"^^rdfs:Literal
is "semantically equal" to
"Bill Clinton"^^xsd:string.

In this case yes, because plain literals are treated as strings.

>I assume it is.

No, see above.

>hm, and what about

>"1.0"^^xsd:float vs. "1"^^xsd:integer?

In general, it depends on the definitions of the value spaces of datatypes. In the
above example, you should/can check the XML Schema type system.


>I guess, property values have to be validated/adjusted
against the intended range datatype before a hasValue
restriction can be checked..

I don't think this is necessary. The datatype constraints from range axioms and from
typed literals are independent from each other.

Jeff

--
Jeff Z. Pan  ( http://DL-Web.man.ac.uk/ )
Computer Science Dept., The University of Manchester


>now I'm left puzzled as well.. ;)
benjamin

--
Benjamin Nowack

Kruppstr. 100
45145 Essen, Germany

>thanks for any advice,
>
>Dan
>
Received on Friday, 21 May 2004 18:35:41 UTC

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