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Re: Should this schema be invalid?

From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
Date: 02 Aug 2002 10:58:58 +0100
To: Xan Gregg <xan@tibco.com>
Cc: "'Jeni Tennison'" <jeni@jenitennison.com>, Dare Obasanjo <dareo@microsoft.com>, xmlschema-dev@w3.org, Cliff Schmidt <cschmidt@microsoft.com>
Message-ID: <f5bfzxxintp.fsf@cogsci.ed.ac.uk>

Xan Gregg <xan@tibco.com> writes:

> Anyone got any suggestions for improving the restriction rules?  Seems like
> a hard problem to capture the desired sematics "R is a valid restriction of
> B if every valid instance of R is also a valid instance of B" in a set of
> rules that are straightforward to implement.

I'm not sure it's even possible.  I strongly favour moving to the
'extensional' approach, which simplymakes your quoted phrase above the
_defintion_ of valid restriction.

As previously noted, I believe we can easily implement this at
'compile time' via coontent model FSM subsumption checking.

  Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
          W3C Fellow 1999--2002, part-time member of W3C Team
     2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
	    Fax: (44) 131 650-4587, e-mail: ht@cogsci.ed.ac.uk
		     URL: http://www.ltg.ed.ac.uk/~ht/
 [mail really from me _always_ has this .sig -- mail without it is forged spam]
Received on Friday, 2 August 2002 06:00:56 UTC

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