# Re: PROV-ISSUE-43 (derivation-time): Deriviation should have associated time [Conceptual Model]

From: Khalid Belhajjame <Khalid.Belhajjame@cs.man.ac.uk>
Date: Sun, 24 Jul 2011 13:27:12 +0100
Message-ID: <4E2C0FA0.7030400@cs.man.ac.uk>
To: Paul Groth <p.t.groth@vu.nl>
CC: Provenance Working Group WG <public-prov-wg@w3.org>, Provenance Working Group Issue Tracker <sysbot+tracker@w3.org>
```
Hi Paul,

On 24/07/2011 13:13, Paul Groth wrote:
> Hi Khalid
> But why can't I say that a newspaper article is derived from a picture at a particular time? Or for that matter over a period of time.

The way I see it, is that there will be a bob representing the newspaper
article and another representing the picture. If there is evidence that
the latter is derived from the former, then the derivation will always
hold between those two bobs.

Now, that I am writing this email, I am wondering whether we are
referring to the same notion of time. In your statement,
isDerivedFrom(b1,b2,t), I think you mean t is used to refers to the time
in which the derivation assertion was made, whereas what I was thinking
of is the (period of) time in which the derivation holds. Is that the case?

Thanks, khalid
> The time is when the derivation occurred not when it applies.
>
> Thanks
> Paul
>
> On Jul 24, 2011, at 13:06, Khalid Belhajjame<Khalid.Belhajjame@cs.man.ac.uk>  wrote:
>
>> Hi Paul,
>>
>> I think that "Use" and "Generation" should be associated with time.
>> However, I don't think we should associate time to derivation.
>> I would argue that isDerivedFrom(b1,b2) holds all time. Although b1 and
>> b2 may no longer exist, isDerivedFrom(b1,b2) is still valid.
>>
>> Thanks, khalid
>>
>>
>> On 23/07/2011 16:46, Provenance Working Group Issue Tracker wrote:
>>> PROV-ISSUE-43 (derivation-time): Deriviation should have  associated time [Conceptual Model]
>>>
>>> http://www.w3.org/2011/prov/track/issues/43
>>>
>>> Raised by: Paul Groth
>>> On product: Conceptual Model
>>>
>>> Other relationships have time associated with them (e.g. use, generation, control)
>>>
>>> There is no optional time associated with derivation.
>>>
>>> Suggested resolution is to add the following to the definition of isDerivedFrom:
>>>
>>> -  May contain a "derived from time" t, the time or time intervals when b1 was derived from b2
>>>
>>> Example:
>>> isDerivedFrom(b1,b2, t)
>>>
>>>
>>>
>>>
>>>
>>>
>>
```
Received on Sunday, 24 July 2011 12:27:43 UTC

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