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Re: How to state simple facts in RDF

From: Frank Manola <fmanola@acm.org>
Date: Wed, 29 Jun 2005 10:45:43 -0400
Message-ID: <42C2B417.7090700@acm.org>
To: "Uschold, Michael F" <michael.f.uschold@boeing.com>
CC: "McBride, Brian" <brian.mcbride@hp.com>, Lars Marius Garshol <larsga@ontopia.net>, public-swbp-wg@w3.org

I think Mike's comment identifies the key distinction here.  The 
original examples "this case is closed", "this company is bankrupt", and 
"this article is a draft", and Mike's examples "my car is red" and "this 
food tastes good", have in common that no property name is explicitly 
given (unless you count "is").  Using classes, as in rdf:type, attempts 
to preserve this "propertyless" syntax, although by using rdf:type as a 
sort of generic property.

Generally speaking, you only have two choices here:  you can describe 
things has having certain properties and values, or you can describe 
things as being members of certain sets.  So you can say either

ex:myCar ex:hasColor "red"  .

or

ex:myCar rdf:type ex:RedThings  .

--Frank

Uschold, Michael F wrote:
> Rdf:type is fine for many such examples.
> 
> However, it is not always such a good idea to create special
> classes/types for every such fact.
> For example: 
> 	My car is red.
> 	This food tastes good.
> 
> To use rdf:type food these statements requires one to create artificial
> classes/types for such notions as RedThings, or GoodTastingThings.
> 
> One can do it, but it is not always what you want.
> 
> Mike
> 
> 
> ============================================
> Mike Uschold
> Tel: 425 865-3605              Fax: 425 865-2965
> ============================================
> 
> 
> 
> 
>> -----Original Message-----
>> From: McBride, Brian [mailto:brian.mcbride@hp.com] 
>> Sent: Tuesday, June 28, 2005 1:18 AM
>> To: Lars Marius Garshol; public-swbp-wg@w3.org
>> Subject: RE: How to state simple facts in RDF
>> 
>> 
>> 
>> This question came up in RDFCore.  The suggestion at the 
>> time was to use rdf:type, e.g.
>> 
>>   Eg::company rdf:type eg:BankruptCompany .
>> 
>> Brian
>>  
>> 
>> > -----Original Message-----
>> > From: public-swbp-wg-request@w3.org
>> > [mailto:public-swbp-wg-request@w3.org] On Behalf Of Lars 
>> > Marius Garshol
>> > Sent: 27 June 2005 15:00
>> > To: public-swbp-wg@w3.org
>> > Subject: How to state simple facts in RDF
>> > 
>> > 
>> > 
>> > In the work of the RDFTM task force the issue of how simple
>> > facts are represented in RDF has come up, since the task 
>> > force needs to find a way to express such facts in RDF.
>> > 
>> > It's probably not clear what I'm talking of here, but
>> > examples are statements like "this case is closed", "this 
>> > company is bankrupt", "this article is a draft", and so on.
>> > 
>> > How do people usually express this in RDF, and what is the 
>> "best" way? 
>> > The task force thought of several alternatives, but would be 
>> > interested to hear what the best practice is, if there is one, and 
>> > what individuals think, if there is no best practice.
>> > 
>> > -- 
>> > Lars Marius Garshol, Ontopian         <URL: 
>> http://www.ontopia.net >
>> > GSM: +47 98 21 55 50                  <URL: 
>> > http://www.garshol.priv.no >
>> > 
>> > 
>> > 
>> 
>> 
> 
> 
> 
Received on Wednesday, 29 June 2005 14:34:14 UTC

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