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Re: Patel-Schneider Paradox ...

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Fri, 15 Feb 2002 02:27:33 -0500
Message-Id: <p0510143ab8926649d902@[]>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: Dan Brickley <danbri@w3.org>, webont <www-webont-wg@w3.org>
>From: Dan Brickley <danbri@w3.org>
>Subject: Re: Patel-Schneider Paradox ...
>Date: Fri, 18 Jan 2002 17:00:34 -0500 (EST)
>>  RDF 1.0 was
>>  kept pretty simple, and it isn't suprising that we're pushing at the
>>  limits of what we can get done with such a simple representational system.
>>  Dan
>I just cannot let this statement go by without registering the strongest
>I believe that RDF is *not* simple.  On the contrary, I firmly hold the
>view that RDF is one of the most complex representation formalisms I have
>ever encountered.
>Complexity is not (solely) measured by the amount of implementation effort
>required to build a minimal parser for a language, although even building a
>minimal parser for RDF is considerably more complex than building a minimal
>parser for many representation formalisms.  Complexity also has to do with how
>hard it is to understand the syntax of a representation formalism, how hard
>it is to come up with an understanding of the basic principles of the
>representation formalism, and how hard it is to determine just what the
>constructs of the representation formalism mean, among other aspects.  In
>all three of the above areas RDF is significantly more complex than most
>representation formalisms.

Well, I can't let that go by, either. (Let me see, how to phrase 
this....) Balls.

RDF is about as simple as a representational language could possibly 
be. It is first-order positive existential conjunctive logic 
restricted to binary relations. Period. (Oh, well, it also has 
datatyping for literals, but that isn't very complicated either.)

There is nothing complex or difficult about it. It is easy to map it 
into a conventional logical notation, and trivial to map it into KIF. 
Its entire proof theory can be captured in one lemma (see the MT 
document) and its model theory can be written on a postcard. Parsing 
the graph syntax can be done by a finite-state machine in one pass. 
If you can see any complexity in it, Peter, you must be smoking some 
really good ganja.

Pat Hayes

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Received on Friday, 15 February 2002 02:27:32 UTC

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