W3C home > Mailing lists > Public > www-rdf-interest@w3.org > December 2003

RE: Trust, Context, Justification and Quintuples

From: Jos De_Roo <jos.deroo@agfa.com>
Date: Tue, 23 Dec 2003 00:52:32 +0100
To: "David Menendez <zednenem" <zednenem@psualum.com>
Cc: www-rdf-interest@w3.org, Graham Klyne <gk@ninebynine.org>
Message-ID: <OFCFCFAC4C.262E5F20-ONC1256E04.007F0E37-C1256E04.00833095@agfa.be>

David Menendez writes:
> Jos De_Roo writes:
>> Using <uri-of-some-set-of-triples> as an example
>> was misleading. We normally identify the *document*
>> on which the rdf formula is written and so it would
>> have been better when I would have used
>> <uri-of-some-rdf-document> and then I still think
>> that we *call* some-set-of-triples
>> <uri-of-some-rdf-document>!log:semantics
> Does <uri-of-some-rdf-document> indicate a resource available through
> the web? If so, is the assumption that log:semantics may relate the same
> resource to different graphs over time?

I believe so...

> For example, Alice might post a FOAF profile at
> <http://example.com/alice>, leading to this data:
>     <http://example.com/alice> log:semantics {
>         _:a rdf:type foaf:Person.
>         _:a foaf:mbox <mailto:alice@example.com>.
>         _:a foaf:name "Ailce".
>     }.
> The next day, she fixes the typo, and we get:
>     <http://example.com/alice> log:semantics {
>         _:a rdf:type foaf:Person.
>         _:a foaf:mbox <mailto:alice@example.com>.
>         _:a foaf:name "Alice".
>     }.
> This means we can't treat <http://example.com/alice>!log:semantics as an
> identifier of a specific graph, because it indicates different graphs at
> different times.

It is indeed true that it could indicate different graphs at
different times.

There are several aspects of meaning in RDF which are ignored
by this semantics; in particular, it treats URI references as
simple names, ignoring aspects of meaning encoded in particular
URI forms [RFC 2396] and does not provide any analysis of
time-varying data or of changes to URI references.
]] -- http://www.w3.org/TR/rdf-mt/

or in an earlier draft

Similarly, the model theory given here has no special provision
for tracking temporal changes; it assumes, implicitly, that
URIs have the same meaning whenever they occur. (If one wishes
to apply RDF in a context where the referents of URIs (or names
more generally) may change with time, then the current theory
could be regarded as defining a 'snapshot' of the meaning of a
changing representation.)
]] -- http://www.w3.org/TR/2001/WD-rdf-mt-20010925/

I believe that the 'snapshot' idea can be engineered
(put into engines :-))

Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
Received on Monday, 22 December 2003 18:52:40 UTC

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