W3C home > Mailing lists > Public > www-rdf-logic@w3.org > May 2001

RE: What do the ontologists want

From: Graham Klyne <GK@ninebynine.org>
Date: Sun, 20 May 2001 09:53:16 +0100
Message-Id: <5.0.2.1.2.20010520094441.03947370@joy.songbird.com>
To: pat hayes <phayes@ai.uwf.edu>
Cc: www-rdf-logic@w3.org
At 02:39 PM 5/18/01 -0500, pat hayes wrote:
>>At 09:31 PM 5/17/01 -0500, pat hayes wrote:
>>>>in RDF:
>>>>
>>>>3: a statement is not a predicate.
>>>>4: a statement is not a resource.
>>>
>>>? I thought a resource could be anything (?) I am still trying to find 
>>>out what 'resource' means, but Dan Connolly tells me that:
>>>the standard [definition of resource] is RFC2396:
>>>
>>>[[[
>>>     Resource
>>>        A resource can be anything that has identity.
>>>        [...]
>>>]]]
>>>
>>>which seems to cover just about anything in the universe, certainly 
>>>including RDF statements.
>>
>>But if a statement does not have an identity?
>
>How can anything not have an identity? Everything has an identity. (?? 
>Maybe 'having an identity' means something special here that I am not 
>following? I take it that to have an identity means to be equal to 
>oneself, ie to exist.)

Er, yes, I guess I took an unjustified leap there.

I interpolated "has identity" excerpted from RFC2396 as "has an identifier" 
or even "has a URI".  On reexamination, I see that text does not justify 
this conclusion.

If "has identity" means simple "exists" as you suggest, I'm not sure that 
this snippet of definition is really very helpful:  is anything excluded?

>>Dan's/Mel99 model theory had:
>>
>>   N: the set of resources
>>   S: the set of statements, a subset of (NxNxN)
>>
>>[...]
>>>>6: a resource clearly doesn't need to be reified to have a statement
>>>>made about it.
>>>
>>>Not obvious to me at present.
>>
>>What does it mean to reify a _resource_?
>
>I'm not the person to ask: I still do not have any clear idea what 
>"resource" means, and am trying to find out. Actually what would be more 
>use would be to see some examples of non-resources.

My comment was intended to point to "reification" in RDF typically being 
understood as appliyiung to a _statement_.

As for your latter comment: me too, now.

#g


------------
Graham Klyne
(GK@ACM.ORG)
Received on Monday, 21 May 2001 06:28:34 UTC

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