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Re: ACTION NW xmlChunk-44: Chunk of XML - Canonicalization and equality

From: Henry S. Thompson <ht@inf.ed.ac.uk>
Date: Thu, 26 Aug 2004 19:52:08 +0100
To: Norman Walsh <Norman.Walsh@Sun.COM>
Cc: www-tag@w3.org
Message-ID: <f5b4qmpohpj.fsf@erasmus.inf.ed.ac.uk>

Norman Walsh <Norman.Walsh@Sun.COM> writes:

> I don't see why the comparison function should be doing validity
> checking. You have an infoset. An infoset is a bag of properties. I
> don't care where you got it from or how you constructed it.

I absolutely agree -- you misunderstood one aspect of my email, see below.

> | I hope that's not the answer, in which case I'd be interested not only
> | in a specific explanation of why the [in-scope namespaces] EII
> | property was not included, but also in the more general question of
> | the implicit suggestion above that "Everyone knows what 'well-formed'
> | means when applied to infosets" and "It doesn't make sense to define
> | equivalence such that a well-formed infoset can be equivalent to a
> | non-well-formed infoset."
>
> I hope my explanation above goes some way to expressing how I feel
> about the answer to those questions.

Not really -- you haven't explained why it's OK for two infosets to be
equivalent despite one being 'well-formed' and the other not -- I like
to think of members of equivalence classes as being inter-substitable
for most important purposes, and serialisability is pretty
important. . .

This is _not_ to say that the equivalence test should check some
definition of well-formedness, but rather that all (most) information
item properties on which well-formedness depends should be included in
the domain of the equivalence test.

ht
-- 
 Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
                     Half-time member of W3C Team
    2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
            Fax: (44) 131 650-4587, e-mail: ht@inf.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 Thursday, 26 August 2004 18:52:13 GMT

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