- From: Graham Klyne <GK@ninebynine.org>
- Date: Sun, 18 Sep 2011 22:16:43 +0100
- To: Satya Sahoo <satya.sahoo@case.edu>
- CC: "Myers, Jim" <MYERSJ4@rpi.edu>, W3C provenance WG <public-prov-wg@w3.org>
On 18/09/2011 19:52, Satya Sahoo wrote: > Hi Jim and Graham, > >> 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). > > > I believe modeling a document d1 versus modeling versions of document d1v1, > d2v2 are two distinct notions. d1, d1v2, d1v2 are surely different things, but I don't see that modelling them is fundamentally different. What sorts of things can one say about d1v1/d1v2 that one cannot say about d1? And vice versa? > The d1v1 and d2v2 are specialized (maybe > subclass) notions of d1. Also, modeling concepts such as d1v1, d2v2 are not > required by all provenance applications. > > >> For example, OPMV avoids this whole issue by saying that the things to > which provenance are applied are>static [1]. > The OPMV has used the original OPM Artifact definition and hence the OPM > notion of "static" Artifact. Certainly - my point was that it doesn't prevent one from describing (say) d1v1, d1v2, etc. and also separately saying that they arr "versions" of d1. And it's a *lot* simpler than the current proposal. #g -- > On Sun, Sep 18, 2011 at 6:20 AM, Graham Klyne<GK@ninebynine.org> wrote: > >> Jim, >> >> >> On 17/09/2011 16:15, Myers, Jim wrote: >> >>> 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). >>> >> >> Agreed, we need to be able to distinguish between the document and its >> "versions" for which some values about which we make provenance assertions >> are invariant. >> >> >> (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). >>> >> >> I take a view that something may be a "version" of something else if it is >> asserted to be (*). The important consequence of being such a "version" is >> that valid provenance assertions made with respect to these versions are >> permanent truths, and can they can be said to be about some aspect of the >> original resource. Beyond that, why do we need to know what are the >> particular constraints for a particular "version"? >> >> I guess I'm trying to dodge the philosophical minefields about what >> constitutes identity. I'm more concerned with what we need as a minimum to >> be able to record, exchange and do useful things with provenance >> information. >> >> It could be that I'm missing something important here, hence my original >> question being phrased as "what breaks?" >> >> ... >> >> You also raise what I see as a separate issue: "a version is really a >> different kind of thing than a document". In some senses, this is almost >> tautologically true, but from a perspective of ontologizing, I'm not sure >> it's useful. Can versions have versions (I think so). Then we are faced >> with a potentially infinite regress of types, or a type that can be >> reflexive (if that's an allowable use) with respect to the version >> relationship; i.e. a type that can be both range and domain of a "has >> version". To me, the latter seems to be the simpler course, unless and >> until we find some essential functionality that is broken in such an >> approach. >> >> ... >> >> (*) of course, it may be of interest to others to understand what makes >> something a "version" of something else, and to understand the variant and >> invariant elements in detail. I'm just asking if this needs to be part of >> the _provenance_ discussion, or if it can be treated separately. >> >> For example, OPMV avoids this whole issue by saying that the things to >> which provenance are applied are static [1]. This is enough for OPMV to be >> useful in a significant range of applications for provenance (I understand >> it is used in the current UK open gov data work). I personally think that >> might be too strong a constraint, but if the price of relaxing that >> constraint is to wade into difficult philosophical territory, them I'm not >> so sure it's worth it. >> >> The fact that the things OPMV describes may be different versions of some >> underlying thing is simply not part of this particular ontology, and it >> seems to work OK so far. >> >> [1] http://open-biomed.**sourceforge.net/opmv/ns.html#**sec-specification<http://open-biomed.sourceforge.net/opmv/ns.html#sec-specification>- see sub-section on "Artifact" >> >> #g >> -- >> >> >> >> -----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<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 Sunday, 18 September 2011 21:17:41 UTC