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All value spaces are partially ordered.

From: Matthew Fuchs <Matthew.Fuchs@westbridgetech.com>
Date: Fri, 29 Aug 2003 14:23:12 -0600
Message-Id: <>
To: W3C XML Schema Comments list <www-xml-schema-comments@w3.org>

Dave is right.  The null relation, null(a, b) = false for all values of a 
and b:

For no a in the value space null(a,a).

For all a and b in the value space null(a, b) implies not(null(b,a)).

For all a, b, and c in the value space null(a, b) and null(b, a) implies 
null(a, c).

(Note that the second point is just f -> ~f == ~f \/ ~f == t, and the third is

(f /\ f) -> f == ~(f /\ f) \/ f == t \/ f == t)

Received on Friday, 29 August 2003 16:23:47 UTC

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