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Re: Another try.

From: Dan Brickley <danbri@danbri.org>
Date: Tue, 28 Feb 2012 17:37:12 +0100
Message-ID: <CAFfrAFrgcsUY89vjvT1-PFrMOOYa4cDiZ4NQzs6AOTbR38S3Xw@mail.gmail.com>
To: Pat Hayes <phayes@ihmc.us>
Cc: RDF-WG Group <public-rdf-wg@w3.org>
On 28 February 2012 16:54, Pat Hayes <phayes@ihmc.us> wrote:

> First, it was abundantly clear from the very beginning of the RDF WG activity that RDF/S (and DAML/OIL and subsequently OWL) were understood to be timeless logical languages.

Put it this way...

The first public RDF Working Draft, http://www.w3.org/TR/WD-rdf-syntax-971002/

<?namespace href="http://docs.r.us.com/bibliography-info" as="bib"?>
<?namespace href="http://www.w3.org/schemas/rdf-schema" as="RDF"?>
<RDF:serialization>
  <RDF:assertions href="http://www.bar.com/some.doc">
    <bib:author>
      <RDF:resource>
        <bib:name>John Smith</bib:name>
        <bib:email>john@smith.com</bib:email>
        <bib:phone>+1 (555) 123-4567</bib:phone>
      </RDF:resource>
    </bib:author>
  </RDF:assertions>
</RDF:serialization>

While the document's author may be eternally the same, John's name,
email and phone are likely more volatile. While the schema's author
could've baked temporally-qualifying observations into the prose of
the property definition (e.g. 'current or former...'), in practice few
do this.

<?namespace href="http://www.nist.gov/RDFschema" as="NIST"?>
<?namespace href="http://www.w3.org/schemas/rdf-schema" as="RDF"?>
<RDF:serialization>
  <RDF:assertions href="John_Smith">
    <NIST:weight>
      <RDF:resource id="weight_001">
        <NIST:units href="#pounds"/>
        <RDF:PropValue>200</RDF:PropValue>
      </RDF:resource>
    </NIST:weight>
  </RDF:assertions>
</RDF:serialization>

... not to mention his weight.  (And I wish I weighed now what I
weighed in 1997.)

Anyway, this pretty much set the tone for everything that followed, in
terms of RDF-in-practice.

I know perfectly well you could've made us a lovely temporal logic or
whatever instead; but the RDF Core job wasn't to do that, but to come
up with a more formal story that covered as much as possible of
RDF-in-practice. Which it did, except for the aspect that people
stubbornly keep defining and using properties for stuff that changes,
even if the smallprint says not to. We went as far as we could without
creating another place to stuff information. It seems now we're
considering doing just that.

>  So if Dan or anyone else is thinking that RDF is going to eventually become a time-embedded language in which assertions have a temporal state, then forget it.

I don't believe I suggested that, and I like the direction of your
recent proposals.

cheeers,

Dan
Received on Tuesday, 28 February 2012 16:37:45 UTC

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