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Re: Comments on ioctl (was: Re: big issue (2001-09-28#13))

From: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
Date: Sat, 06 Oct 2001 09:52:43 +0100
Message-Id: <5.1.0.14.2.20011006094349.037dc0e0@joy.songbird.com>
To: Pat Hayes <phayes@ai.uwf.edu>
Cc: Jan Grant <Jan.Grant@bristol.ac.uk>, w3c-rdfcore-wg@w3.org
At 11:51 AM 10/5/01 -0500, Pat Hayes wrote:
>However, what I think IS characteristic of all kinds of literal is, that 
>they bear a very close kind of relationship to their denotations, in that 
>one can *compute* the denotation from the literal. It wears its meaning on 
>its sleeve, as it were. You don't need to go off looking for assertions 
>*about* its meaning; you can tell just by looking at the literal itself 
>what its denotation is (maybe using some literal-defining conventions , 
>e.g. knowing that it is a decimal numeral written from left to right, but 
>those are fixed outside the assertional language and are considered part 
>of the lexical definition of the vocabulary.) Obviously,  being its own 
>denotation is a particularly simple case of that, but its not the only 
>possible case. So Id suggest altering this to:
>
>a literal is a name whose denotation can be computed from the name alone

Yes!  I think this captures something I've been struggling to 
articulate.  (I read this after my recent post to RDF-logic.)


>-----
>
>Can a literal label an arc? Well, that is up to the Arc Police, ie us; 
>but, *could* a literal label an arc? Yes, as far as the model theory is 
>concerned, though that would have some fall-out in the treatment of 
>literals in RDFS. Right now the MT tries hard to keep literals at a safe 
>distance, as it were, since their status is cloudy, and to maintain that 
>hands-off style while also allowing literals as subjects or arc labels 
>would be tricky. But if we were to take some kind of Big Decision to allow 
>literals to be more closely integrated with the things URIs denote, then 
>the MT would actually get easier. Easiest of all from the MTs point of 
>view would be to just toss URIs and literals all together and give them a 
>uniform semantics

Hmmm... according to the MT as it stands, the thing denoted by an arc label 
must have an extension which is the set of pairs that can appear at each 
end of the arc.  Is it reasonable that this set can be computed from the 
literal used to label the arc?

I suppose so:  I can imagine an arc label "<", for which one can compute a 
relational extension:
    { <"0","1"> <"0","2"> <"0","3"> ...
      <"1","2"> <"1","3"> ...
      etc.  }

(Practical rules of computation would need to take into account other 
details like signs, leading zeros, nu8mber base, other lexical variations 
of number representation.  I suppose that arc-label literal should be 
"decimal<" or suchlike.)

#g


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Graham Klyne                    MIMEsweeper Group
Strategic Research              <http://www.mimesweeper.com>
<Graham.Klyne@MIMEsweeper.com>
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Received on Saturday, 6 October 2001 05:00:03 EDT

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