Re: reifying variables

From: Peter F. Patel-Schneider (
Date: 02/12/04

  • Next message: Sandro Hawke: "Multiple Semantic Web Languages (was: Re: reifying variables)"
    From: Sandro Hawke <>
    Subject: Re: reifying variables 
    Date: Thu, 12 Feb 2004 09:48:30 -0500
    > > From: Sandro Hawke <>
    > > Subject: Re: reifying variables 
    > > Date: Thu, 12 Feb 2004 08:08:30 -0500
    > > 
    > > > 
    > > > > > So SWRL makes no claim to get it right, which is okay, but of course
    > > > > > this means it's not really an "RDF Concrete Syntax", it's an "RDF-Like
    > > > > > Concrete Syntax."   Not so good.
    > > > > 
    > > > > Well, this is probably the best that can be done.
    > > > 
    > > > In what way is it better to use an "RDF-Like" syntax?  That seems to
    > > > me like the worst of both world -- all the syntactic beauty and
    > > > convenience elegance of RDF/XML, plus all the standard-ness of the
    > > > <blink> tag.
    > > > 
    > > >   -- sandro
    > > 
    > > Technically I don't see any reason to use an RDF syntax whatsoever.
    > > However, using RDF syntax has appeared to be the price to enter the
    > > Semantic Web arena.
    > I understand Jim Hendler made it the price of admission to the DAML
    > program, when he was Program Manager.  Beyond that, I'm not sure.  I
    > think the W3C gives mixed signals, sometimes using n3 instead.  
    I argued long and loud in the W3C WebOnt working group about problems that
    using the RDF syntax caused.  This argument didn't go anywhere, so I gave
    in and created a partial solution for OWL.  (Academically this was a great
    success, as I was able to get some research papers out of my involvement
    with the working group, but I'm not so sure whether this was a practical
    > I've
    > sometimes campaigned unsuccessfully for a standard meta-language, in
    > which the syntax and semantics of practical data languages are
    > described.
    XML might be the syntax half of this.  Isn't model theory (or even
    mathematics) the semantics half?  :-)
    > In any case, using an "RDF-Like" syntax is using counterfeit money and
    > I suspect is only accepted as the price of admission by mistake.  I
    > apologize for not noticing and commenting on SWRL doing this back in
    > November.
    There have been several proposals to make this sort of solution the
    official one, including things like dark triples.  I don't like the RDF
    syntax, and don't believe that uninterpreted triples are a good solution to
    the problem.  I would very much welcome a statement from W3C that Semantic
    Web languages do not have to be written in triples (or quads, or quints,
    ..., as in several recent proposals).
    > > I would be much, much happier if the Semantic Web had multiple syntaxes.  I
    > > have argued this in the past, to no avail, and have even written papers
    > > proposing multiple-syntax versions of the Semantic Web.  I don't see any
    > > technical reasons to not go to a multiple-syntax version of the Semantic
    > > Web.
    > You would agree there's a cost to each new language, right?  
    No.  I do not believe that there is a net cost for most new
    languages/representations.  New languages/representations are accepted in
    part because of problems with existing languages/representations.  If the
    new language/representation does not have benefits outweighing its costs,
    it is unlikely to be accepted.
    > Having
    > hundreds of languages isn't practical (unless some meta-language
    > approach is used, but then there aren't really hundreds of languages).
    Well, what using XML, and having multiple Schemas/DTDs for the different
    semantic languages?  This certainly cuts the cost of parsers!
    > I've occasionally heard the observation that markets can generally
    > support two standards.  In this case, RDF/XML sets a pretty low bar
    > for the competition.  I think the RDF model itself is a pretty high
    > bar, but time will tell.
    >     -- sandro
    Well, the Web has quite a number of languages/representations, even if you
    only count the major ones.  A partial list is
    (the above are from the Web Architecture document) 
    Some of these are XML dialects but some are not.  Current web browsers can
    handle lots of different languages/representations, and can be configured
    to get outside help to handle others.

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