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Re: A shot at http://www.w3.org/2000/03/rdf-tracking/Overview.html#rdfms-resource-semantics

From: <jos.deroo.jd@belgium.agfa.com>
Date: Tue, 8 May 2001 22:46:57 +0100
To: bwm@hplb.hpl.hp.com
Cc: martyn.horner@profium.com, w3c-rdfcore-wg@w3.org
Message-Id: <OF4C1FF3A7.0D1BA2CC-ON41256A46.00779315@bayer-ag.com>

Hi Brian,

[...]
> I recently tried to articulate the working model that I use and it came
> out something like this:
>
>  There is a set of resources R.
>
>  Each member of R is identified by a URI by which I mean:
>
>    r1.uri == r2.uri <=> r1 == r2
>
>  i.e. two resources are identical if they have the same URI.
>  two resources with different URI's are different resources.

I actually learned (not in school) that
  r1.uri == r2.uri => r1 = r2
but not the other way around
so *each* uri denotes/identifies *a* resource
but *a* resource could be denoted/identified by * (0 or more) uri's

>  There is a set E of entities.  Entities are things like web pages,
>  numbers and trees in the park.

[[[entity
     The information transferred as the payload of a request or
     response. An entity consists of metainformation in the form of
     entity-header fields and content in the form of an entity-body, as
     described in section 7.
     -- http://www.ietf.org/rfc/rfc2616.txt
        http://www.w3.org/Protocols/rfc2616/rfc2616-sec1.html#sec1.4
]]]

>  There is a mapping D : R -> E.  i.e. there is mapping which maps resources
>  to entities.
>
>  There is a notion of equivalence.
>
>  Two resources r1 and r2 can be mapped by D to the same entity.  In that case
>  we say they are equivalent.
>
>    equiv(r1,r2) <=> D(r1) = D(r2)
>
>  and finally:
>
>    D((p,s,o)) <=> D(p)(D(s),D(o))

so the mapping of a triple resource is equivalent with ???

> I present this, not because I claim it is correct, it doesn't deal with frag
> id's for example, but to suggest a language in which we can be clearer about
> what we mean.

That's indeed very useful!

--
Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
Received on Tuesday, 8 May 2001 16:51:19 EDT

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