W3C home > Mailing lists > Public > public-prov-wg@w3.org > March 2012

Re: PROPOSALS TO VOTE ON (deadline: Wednesday 14th, midnight GMT)

From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Date: Tue, 13 Mar 2012 22:24:53 +0000
Message-ID: <EMEW3|7578dcc771c41adc7f96742ddb7e9eb7o2CMQG08L.Moreau|ecs.soton.ac.uk|4F5FC935.2040109@ecs.soton.ac.uk>
To: public-prov-wg@w3.org
Hi Curt,

Responses interleaved.

On 13/03/12 20:02, Curt Tilmes wrote:
> On 03/13/2012 07:59 AM, Luc Moreau wrote:
>>> So if I, for example, download those proceedings prior to their
>>> disappearance, then at some later time, perform some activity based on
>>> those proceedings, while my activity "used" the proceedings
>>> themselves, it doesn't (can't) use the entity chicago:wkshp2002, which
>>> no longer exists.
>> I would write this as follows:
>> entity(chicago:wkshp2002,[prov:type="workshop talks"])
>> activity(ex:download)
>> entity(ex:wkshp2002copy)
>> wasGeneratedBy(ex:wkshp2002copy,ex:download)
>> used(ex:download,chicago:wkshp2002, t1)
>> wasInvalidated(chicago:wkshp2002, t2)
>> activity(ex:otherAction)
>> used(ex:otherAction, ex:wkshp2002copy, t3)
>> where t1 < t2 < t3
> Your examples seems to be conflating the URI that is the identifier
> for the entity with the URL from which the content (bunch of bits)
> that make up that entity are available.

Isn't it what we want to do in so called "scruffy" provenance. When a 
has a natural identifier (here the URL), we want to reuse it.

> I sometimes use URIs for things that are different from the URL from
> which their content is available (and for some things that aren't
> available through that URL at all like ex:curt -- you might get some
> information about me at ex:curt, but you can't actually download me
> from there).

I agree with you.

We could also have described this entity as follows:


The idea of invalidation/expiry still holds, since that entity is no 
longer at that location after t2.

wasInvalidated(urn:uuid:123456, t2)

> I also don't really ever use content from the web directly.  I always
> download it first -- either onto disk or into memory.  I then perform
> some activity using the thing I downloaded.  I don't see the need to
> explicitly describe that download activity every single time (though I
> could see cases where that would be required) Most of the time I would
> just refer to the original entity.

Indeed, we want to allow your kind of usage.

> Anyway, I don't see a need for 'invalidated' for myself, but if
> someone else wants to use it, I don't object to it.  It does have a
> certain symmetry with generation.
>> Can you expand on this suggestion of prov:SupercededBy?  How would
>> it work?
> It is really just the inverse of 'wasRevisionOf'.
> Perhaps superseded implies something slightly stronger, in that it
> suggests that the version superseded is deprecated in favor of the new
> revision.
> We don't really need it since we can just use revision.

OK, thanks for explaining.

> Curt
Received on Tuesday, 13 March 2012 22:26:42 UTC

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