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RE: Identifying reals

From: Miles Sabin <msabin@interx.com>
Date: Fri, 4 Jan 2002 17:25:34 -0000
To: <www-rdf-interest@w3.org>
Message-ID: <69B15B675E99D411A4110008C786DA23020CC90A@exwest_01.interx.com>
Mark Baker wrote,
> Ah, I missed the "URIs are a finite sequence ..." assumption.
> The problem is that this assumption is incorrect.


If you look closely at RFC 2396 you'll see that URIs are defined by a 
completely ordinary context free grammar. Any good textbook on 
languages and automata theory will tell you that the each member of 
the set of strings conforming a to cfg is finite, and that the set 
itself, the language of the grammar, is at most countably infinite.

Now, there's nothing to stop you, or anyone else, from defining a
class of languages over infinite strings. Actually, you don't have
to, because they are used occasionally. But not for the purposes of 
defining languages intended for machines to parse, and there's 
certainly not the slightest whiff of evidence that any such thing is 
being applied in RFC 2396.



Miles Sabin                                     InterX
Internet Systems Architect                      27 Great West Road
+44 (0)20 8817 4030                             Middx, TW8 9AS, UK
msabin@interx.com                               http://www.interx.com/
Received on Friday, 4 January 2002 12:26:45 UTC

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