RE: Literals (Re: model theory for RDF/S)

>  > > Good point. But again, that has nothing to do with the
>>  > proposed encoding
>>  > of literals as URIs. The very same problem exists with
>>  >
>>  >  #Susan #favorite-integer "05" .
>>  >  #Susan #favorite-integer "5" .
>>  > 
>>  > Right?
>>
>>  Not necessarily.  It depends on whether 'int:' implies some special
>>  processing that strips leading zeroes, or (with an approach
>>  that rohibits
>>  semantically vacuous alternatives) whether the parser can
>>  recognise int:05
>>  as prohibited and throw an error, or merely return undefined results.
>
>No, I meant the present treatment by RDF (not DAML+OIL) of the above
>pair of statements which are not the same statement, yet intuitively
>one would think they represent the equivalent knowledge (though they
>might not...)
>
>My point was that whether you have some typed anonymous node
>pointing to a literal string value or a URI scheme that contains
>a typed value, the same issue exists. It's not *created* just
>because you start using URIs for typed data literals.

That is true. The general issue of how to handle equality in an 
assertional language is going to be there, and treating literals as 
identifiers only reduces literal equivalence to that general problem. 
In effect, though, this seems like a proposal to abandon the notion 
of literal altogether, as far as the language semantics is concerned. 
It seems more like a step backwards than a step forwards. Unlike 
general names, literals have the character that one *almost* can 
determine identity of reference from syntactic identity. That is the 
whole point of using literals in the first place, after all: it is 
why we write '5' rather than 'the successor of the successor of the 
successor of the successor of the successor of zero'. So tossing this 
aspect of literals aside, as it were, because we are having some 
problems making it work *perfectly*, seems rather draconian, for all 
practical purposes (I say 'practical' since it would certainly make 
my job easier when writing the model theory.)

Pat Hayes


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Received on Wednesday, 3 October 2001 17:48:26 UTC