Re: PROV-ISSUE-79 (provenance-uri-contract): what is the contract associated with provenance-uris [Accessing and Querying Provenance]

Hi Graham,

I think the important thing is that we don't say anything about how 
provenance information must be maintained. That is to say that the 
provenance information referred to by a provenance-uri may change over time.

If I add some more detailed provenance information about a resource, I 
can still use the same provenance-uri.

Is that correct?

Thanks,
Paul


Graham Klyne wrote:
>
> On 23/08/2011 12:05, Provenance Working Group Issue Tracker wrote:
>> PROV-ISSUE-79 (provenance-uri-contract): what is the contract associated with provenance-uris [Accessing and Querying Provenance]
>>
>> http://www.w3.org/2011/prov/track/issues/79
>>
>> Raised by: Luc Moreau
>> On product: Accessing and Querying Provenance
>>
>> The PAQ document indicates that provenance information (sometimes referred to as provenance resource) may change over time.
>
> Where does it say that?  If it does, I think it's a mistake.
>
> What's the implication for the provenance-uri?  Is the provenance-uri a cool
> URI?  I think it is not, but this should be made explicit.  There are also
> further issues.
>> Generally, what is the "contract" associated with this provenance-URI? How long should the server be able to serve this URI?  It's particularly important for dynamically generated pages.
>
> IMO, any contact for longevity of retrievability of the resource is outside
> scope of the spec.  We can'#t mandate indefinite availability, and nothing else
> would make any sense.
>
> #g
> --
>
>> Let us consider a provenance store, in which provenance assertions gets accumulated. Let us consider a static resource, r, but over time, what we know about r changes, so it may have different provenance information p1 and p2.
>>
>> If r is accessed, and a provenance-uri is returned, and dereferenced a first time, we obtain p1.
>>
>> If r is accessed again, are we expecting to get the same provenance-uri, or a different one if provenance has changed?
>>
>> Now, let us consider r as a dynamic resource. If r changes between the first and second access, is the same provenance-uri supposed to be returned?
>> If it does not change, how do we ever have a guarantee that the provenance information obtained corresponds to the resource representation we obtained?
>>
>>
>>
>>
>>
>>
>>
>

-- 
Dr. Paul Groth (p.t.groth@vu.nl)
http://www.few.vu.nl/~pgroth/
Assistant Professor
Knowledge Representation & Reasoning Group
Artificial Intelligence Section
Department of Computer Science
VU University Amsterdam

Received on Friday, 26 August 2011 03:51:58 UTC