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Re: WOWG: first language proposal

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Thu, 18 Apr 2002 13:47:51 -0500
Message-Id: <p05101527b8e4c2750154@[65.217.30.94]>
To: Ian Horrocks <horrocks@cs.man.ac.uk>
Cc: heflin@cse.lehigh.edu, www-webont-wg@w3.org
>  > [Frank]
>>  > Finally, an important issue will be finding a way to map your abstract
>>  > syntax into XML/RDF and still preserve its simplicity. I believe that in
>>  > order to get a good, intuitive syntax, we'll have to seriously consider
>>  > dropping the idea of using triples to represent the language, i.e., do
>>  > not layer on top of RDF Schema (but this is a point I've already raised
>>  > in another thread).
>  > [Peter]
>  > Again, a great idea.  The abstract syntax sort of alludes to this in that
>>  the fact portion is written the way it is so that it can easily be mapped
>>  into RDF/XML but the non-fact portion is different from RDF/XML.
>
>I would also vote for this solution. Using RDFS causes many very
>serious problems, e.g., it is an awful syntax specification language
>(look at the trouble with lists, verbosity, unconstrainedness etc.)
>and is difficult/complex to use as a semantic foundation for a more
>powerful language (look at the problems pointed out by Peter).
>
>I asked some time ago what are the great advantages of RDFS that
>justify us paying such a high price - I am still waiting for a
>convincing answer (and considering the price, the answer needs to be
>pretty convincing).

Seems to me that we can define OWL any way we please, and then 
provide a mapping into RDF triples afterwards. Insofar as there are 
parts of OWL that correspond in some natural way to constructs 
already existing in RDFS, then it would be natural to define a 
triples-rendering which used those RDFS constructs in a way that 
preserves as far as possible their RDFS meaning, possibly restricted 
in some way; but I don't think that will be hard to do. This is what 
the DAML JC did, after all: we decided it needed to have expressions 
containing sequences of other expressions, then chose a way to encode 
those sequences into triples. The latter was essentially arbitrary, 
and had no backward influence on the rest of the language. We can 
continue in this great tradition. Then the people who believe that 
RDF is the foundation of the Universe can rest assured that there 
will be a way to declare that OWL 'is' RDF and not actually tell a 
lie, and those who would prefer to ignore RDFS can, well, ignore it. 
I don't think there really is a high price to pay, its more like 
agreeing that XML can be encoded into Sexpressions, if you really 
want to do that, and choosing some way of encoding to be 'the' way. 
If you don't want to encode it in that way, you don't have to. We are 
free to relate the OWL model theory to the RDF model theory in any 
way we see fit.

Pat

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Received on Thursday, 18 April 2002 14:48:04 GMT

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