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

>  > I am unclear as to how this proposal would provide more simplicity or
>>  consistency in either the semantics or the syntax of RDF. 
>
>Fair enough. It certainly has not been presented in any comprehensive
>or organized fashion. I'll do my best to provide a more detailed discussion
>with examples (a work in progress) as soon as possible.
>
>>  What I see in
>>  this proposal is a method for providing a general mechanism
>>  for providing
>>  special cases for RDF.  An RDF processor would have to understand, and
>>  parse, all sorts of different syntax.
>>
>>  Consider the situation with a hypothetical integer scheme.  If an RDF
>>  processor is given
>>
>>  int:5 #loves #Susan .
>>
>>  and
>>
>>  int:05 #loves #Jackie .
>>
>>  then it has to understand that int:5 and int:05 are the same
>>  and respond to a query about the loves of 5 that it #loves
>>  both #Susan and
>>  #Jackie.
>
>Well, not really (IMO)...
>
>It is true that int:5 and int:05 would technically constitute
>different URIs and hence different resources, but that's how
>RDF does things, eh? Different URI, different resource. I'm
>sure we don't want to shift that foundational pillar...  ;-)

The model theory doesn't assume that. Two different URIs can denote 
the same resource (see  http://www.w3.org/TR/rdf-mt/#example1 ). 
However I think that your point here (and throughout) does not really 
depend on this assumption. The point is that two different URIs 
*could* refer to different resources in *some* interpretation. They 
are not forced to co-refer. That is all you need to make your point, 
I think.

>
>Insofar as as a generalized, consistent, global representation
>for a given data type, though, one would expect that there would
>be constraints defined which prohibit semantically vacuous variant
>forms, such as above. So yes, you bring up a very valid requirement
>for e.g. an int: scheme, that we wouldn't get int:00000000005, etc.
>but that's an issue for the particular scheme, not the methdology of
>URI encoded literals itself, I think (apart from specifying it as
>an expected quality of every such scheme to not have semanticly
>vacuous variant forms).

That seems to me a bit like saying that People Should be Good counts 
as a moral code. It may be unreasonable to require all schemes to be 
unique in this way (eg leading zero suppression may be essential in 
some schemes designed to support arithmetic, or consistency with 
programming language conventions); and even if we do, what is to 
prevent there being two different schemes for the same set of values, 
eg two different notational schemes for the natural numbers?

>
>And on a practical level, one would not necessarily expect URI
>encoded literals to act as the subject of statements,

But there would be no way to prevent it, and so the semantics would 
need to support it.


Pat Hayes
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