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Re: datatypes and MT (things versus their names: PRIMER)

From: Dan Brickley <danbri@w3.org>
Date: Tue, 6 Nov 2001 05:06:07 -0500 (EST)
To: Dan Connolly <connolly@w3.org>
cc: Pat Hayes <phayes@ai.uwf.edu>, <jos.deroo.jd@belgium.agfa.com>, <w3c-rdfcore-wg@w3.org>
Message-ID: <Pine.LNX.4.30.0111060436080.15494-100000@tux.w3.org>
On Tue, 6 Nov 2001, Dan Connolly wrote:

> Pat Hayes wrote:
> >
> > >Brian McBride wrote:
> [...]
> > >People often write
> > >   :s eg:shoeSize "10".
> > >   :s nav:date "2001-11-02".
> > >   :s nav:time "16:14".
> > >   :s nav:flightNum "1154".
> > >   :s nav:customerNumber "678".
> > >   :s apt:latitude "50-54N".
> > >   :s apt:longitude "004-32E".
> > >   :s apt:elevation "58M".
> > >or in general
> > >   :s :p "ooo".
> > >and I believe that is a shorthand for
> > >   :s :p [ rdfs:str "ooo" ].
> > >(I used to prefer rdfs:label instead of rdfs:str
> > >but now I think that rdfs:str is a better name for
> > >the property mapping a data value (that bNode)
> > >to it's string representation)
> >
> > I have serious problems with this. For a start, why on earth would
> > anyone say that latitude and longitude and elevation were *strings*?
> > They clearly aren't strings, so this is just plain wrong.
> (a) I agree people write stuff this way, and (b) I agree
> it's just plain wrong, so (c) I think it's critical that
> this issue (things versus their names, numbers vs. numerals...)
> is treated by the primer.
> Case in point: folks write
> 	<dc:creator>Dan Connolly</dc:creator>
> as if a character sequence "D" "a" "n" ... wrote a book.
> It's critical that we teach folks to write
> 	<dc:creator>
> 	  <Person>
> 	    <fullName>Dan Connolly</fullName>
>           </Person>
>         </dc:creator>
> or, more briefly:
> 	<dc:creator contact:fullName="Dan Connolly"/>

Yes, these are crucial distinctions to get right. In the DC case there is
a little more subtlety (or confusion) though: the definition for
http://purl.org/dc/elements/1.1/creator says 'An entity primarily
responsible for...'; but says also (and imho confusingly) 'typically the
name of an entity should be used to indicate the entity'. This is an
invitation to confuse the entity with its name (whether prose name or Web
name aka URI); compounded by suggesting (but not explicitly claiming) that
'the name' of some entity is a single individual (its one name). Or
you could read the 'typically...' observation to be an inline sociological
truism, 'typically this RDF property will be used (like all RDF
properties) in documents that mention the name of the entity it
references'. A confusing jumble, whicheverway you read it.

In the DAML+OIL committee list a while back I grumbled about DAML+OIL's
prose definitions sitting on the word/world fence in an equally painful manner.
The http://www.daml.org/2001/03/daml+oil.daml definitions sometimes say
things like 'for equivalentTo(X,Y), read X is an equivalent term to Y'.
And sometimes they say things like 'for sameIndividualAs(X,Y) read X is
the same individual as Y'. This is either ugly or just plain false, I'm
not sure which.

Dublin Core and DAML+OIL are two rather different 'flagship' RDF/SW apps.
When their schemas make similar confusions about the proper formulation of
RDF schema definitions (ie. confuse terms/names with the individuals they
(hopefully) denote), we should take note.

This should certainly be a priority in the primer; the 'resources vs their
names' murkiness needs to be purged from all corners of the RDF spec, as
well as from specs that try to use RDF.

So: is their someone on the Primer sub-group who owns this problem? what's
the status of this part of the primer? If we don't yet have text drafted
on this, could someone (DanC?) make a stab at writing down a 'best
practice' paragraph or two?


Received on Tuesday, 6 November 2001 05:06:10 UTC

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