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Thoughts on Reification: was: Re: Proposals? Re: use/mention and reification

From: Frank Manola <fmanola@mitre.org>
Date: Thu, 24 Jan 2002 09:01:17 -0500
Message-ID: <3C5013AD.5040705@mitre.org>
To: Jan Grant <Jan.Grant@bristol.ac.uk>
CC: jos.deroo.jd@belgium.agfa.com, connolly@w3.org, w3c-rdfcore-wg <w3c-rdfcore-wg@w3.org>
Jan Grant wrote:

> Can we get small amounts of words to describe these please? Currently
> there seem to be three proposals knocking around, with a possibility of
> others: (insert "this WG resolves that..." in front of all these)
> 

The minutes of the last meeting, under the "reification" section, said 
"We are awaiting an initial gathering of thoughts in a paper from Frank 
M. to kick off discussion."  Fortunately, not very much waiting actually 
took place!  DanC has successfully kicked off the discussion of 
reification, so at least one of the issues involved is being aired, and 
the direction this discussion is taking seems promising.

Overall, the problem is that there are several different ideas about 
reification in the M&S that all (sort of) seem related, are all mixed 
together, but are actually different.  This is the situation we need to 
fix.  We can fix it by eliminating reification entirely (as has been 
suggested), by fixing the existing mechanism so that it consistently 
supports one idea (as has also been suggested), or by providing support 
for more than one of the ideas (if they are independently useful) using 
different mechanisms (although this may be beyond our charter).

Whatever specific decisions we make, it seems to me that we need to 
somehow and somewhere "account for" all the current ideas about 
reification in the M&S.  That doesn't mean we have to *support* all of 
them (or any of them), but rather that somewhere we ought to describe 
what the M&S formerly seemed to say about reification, and how we've 
fixed it (and maybe why), for the benefit of our user community.

Also, I'd like to second Jan's suggestion that we get short descriptions 
of the various proposals (worded so we can vote on them) and collect 
them (Jan's message constitutes a good start IMO). I think this is a 
promising way to actually make progress on this issue.  At the same 
time, I think we ought to simultaneously try to collect short 
descriptions of what applications these proposals are intended to 
support, so we can compare the proposals with what we think we want to 
do with reification.  Examples of these applications (not necessarily 
distinct) include:

a.  describing provenance
b.  including RDF inside other RDF
c.  expressing RDF statements without asserting them
...

The above issues have to do with what a reified statement "means", or, 
alternatively, what we're trying to do when we use reification.  We also 
have a reification thread involving the RDF/XML syntax as it applies to 
reification.  While we're dealing with the "meaning" issues, we also 
need to address how we think reified statements are identified, when 
they are created, and so on, and make sure the XML syntax reflects those
decisions.

--Frank

-- 
Frank Manola                   The MITRE Corporation
202 Burlington Road, MS A345   Bedford, MA 01730-1420
mailto:fmanola@mitre.org       voice: 781-271-8147   FAX: 781-271-875
Received on Thursday, 24 January 2002 08:53:45 EST

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