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RE: Issue 89 - why?

From: Myers, Jim <MYERSJ4@rpi.edu>
Date: Sat, 17 Sep 2011 15:15:30 +0000
To: Graham Klyne <GK@ninebynine.org>, W3C provenance WG <public-prov-wg@w3.org>
Message-ID: <3131E7DF4CD2D94287870F5A931EFC23031657@EX14MB2.win.rpi.edu>
Are you asking whether we need to distinguish between something and 'something that can't change in some ways' to unambiguously record provenance, or just whether frozen attributes is the best way to do that?

If we don't distinguish at all, we have a mess - a document and a version can't be distinguished if we can't talk about fixed content and we'd then be unable to answer questions about when the document was created (with the first version or only when the text was finalized). (This is the problem with things - we don't always agree on what aspects of a thing can change and still be recognizable as the same thing, so we define entities for which the aspects that important relative to the provenance we're recording are clearly changeable or not changeable, not open to interpretation).

If we consider the alternatives to fixing attributes, the most obvious would be to stick the constraint in the type/class - as we do with document and document-version. Either works, but you end up with a lot of type proliferation. 'document-version<#>-at-location<>-inEncoding<>-withEncryption<>' is well defined relative to moving, encoding and encryption changes, etc. The alternative encoding is to fix the attributes. To me, the interpretation should be the same in both cases - a version is really a different kind of thing than a document even if we record it as document with a  fixed content attribute. (The statue and other examples make this clearer).

 Jim


 

> -----Original Message-----
> From: public-prov-wg-request@w3.org [mailto:public-prov-wg-
> request@w3.org] On Behalf Of Graham Klyne
> Sent: Saturday, September 17, 2011 3:07 AM
> To: W3C provenance WG
> Subject: Issue 89 - why?
> 
> I've been reading some of the discussion of Issue 89:
> 
>    http://www.w3.org/2011/prov/track/issues/89
> 
> which seems to my mind be getting rather like a counting of angels-on-
> pinheads, and I wonder if we're not in danger of over-ontologizing here.
> 
> Going back to the original issue, I see:
> 
> [[
> The conceptual model defines an entity in terms of an identifier and a list of
> attribute-value pairs. It is indeed crucial for the asserter to identify the
> attributes that have been frozen in a given entity.
> ]]
> 
> Why is it so crucial to identify what attributes have been frozen?
> 
> What practical application of provenance is prevented is we don't require
> this?
> 
> #g
> --
Received on Saturday, 17 September 2011 15:16:00 GMT

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