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RE: definition of forward compatible/backward compatible still an open problem [XMLVersioning-41 ISSUE-41]

From: David Orchard <dorchard@bea.com>
Date: Fri, 24 Aug 2007 15:46:06 -0700
Message-ID: <BEBB9CBE66B372469E93FFDE3EDC493EA372C3@repbex01.amer.bea.com>
To: "Dan Connolly" <connolly@w3.org>, "www-tag" <www-tag@w3.org>

Right.  Where do we go from here?  You're not comfortable with the
current definition for reasons you've stated.  It also sounds like we
don't have a counter-proposal, and further generating a counter proposal
could involve a huge amount of time in the way of research.

Can we weaken the definition and effectively say it's language
dependent?  

"I1 is compatible with I2 in a language specific manner such that is not
generalizable."

Cheers,
Dave
> -----Original Message-----
> From: www-tag-request@w3.org [mailto:www-tag-request@w3.org] 
> On Behalf Of Dan Connolly
> Sent: Friday, August 24, 2007 2:58 PM
> To: www-tag
> Subject: definition of forward compatible/backward compatible 
> still an open problem [XMLVersioning-41 ISSUE-41]
> 
> 
> The July 4 draft has a revised definition of information 
> compatibility in response to my [21Aug] comments on the 
> defintion of forward/backward compatibility of languages:
> 
> [[
> * Let I1 be the information conveyed by Text T per language L1. 
> 
>   * Let I2 be the information conveyed by Text T per language L2. 
> 
>   * I1 is compatible with I2 if all of the information in I1 does not
>     replace or contradict any information in I2.
> ]]
>  -- http://www.w3.org/2001/tag/doc/versioning
> http://www.w3.org/2001/tag/doc/versioning-20070704.html
> 
> But it still defines compatibility of languages in terms of 
> compatibility of information in a way that doesn't appeal to me.
> 
> That definition of compatibility of information reminds me of 
> the conventional definition of consistency:
> 
> [[
> A theory is said to be satisfiable if it has a model. A 
> theory is consistent if its closure (under the usual rules of 
> inference) does not contain a contradiction. One way of 
> stating the completeness theorem is the following: A theory 
> is satisfiable if and only if it is consistent.
> ]]
>  -- http://en.wikipedia.org/wiki/Model_theory
> 
> ... but there a theory is a text. I'm not familiar with any 
> definition of consistency/compatibility of stuff that the 
> text refers to, i.e.
> "the information conveyed by a text."
> 
> I was part way working thru mappings back in September:
> 
> Re: Re-expressing our formalisation of Language 
> http://lists.w3.org/Archives/Public/www-tag/2006Sep/0040.html
> 
> 
> But I didn't really see how to finish it. And neither did 
> Henry nor Pat Hayes.
> 
> This still feels like an open research problem, to me.
> 
> 
> p.s. Hi tracker. This is progress on, if not completion of, ACTION-4
> http://www.w3.org/2001/tag/group/track/actions/4
> 
> [21Aug] http://lists.w3.org/Archives/Public/www-tag/2006Aug/0084
> 
> 
> --
> Dan Connolly, W3C http://www.w3.org/People/Connolly/
> 
> 
> 
> 
Received on Friday, 24 August 2007 22:46:28 GMT

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