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Simplicity (was: Regarding the definition of IVP OF)

From: Graham Klyne <GK@ninebynine.org>
Date: Tue, 12 Jul 2011 08:51:50 +0100
Message-ID: <4E1BFD16.9060204@ninebynine.org>
To: Khalid Belhajjame <Khalid.Belhajjame@cs.man.ac.uk>
CC: public-prov-wg@w3.org

I understood that the notion "IVP of" was something we adopted to faciliatte 
discussion about the concepts. I personally feel that it should not appear in 
any actual document produced, as I suspect it will continue to beg more 
questions than it resolves, and confusing our readership is not the way to get 
our outputs adopted, to have impact.

Once we have a notion of what we mean, which IMO should be as simple/minimal as 
we can get away with, we should aim to include that meaning directly in the 
model specv without the interlocution of this "IVP" notion.  If a formally 
defined relationship is required, then define it formally within the model terms 
actually used to describe provenance, don't introduce another informal term, 
into the document.

I think all this is true particularly of provenenace.  This is something that we 
ideally want just about every semantic-web-data-producing application to include 
in  their output.  For that to happen (i.e. necessary but not sufficient) the 
specification needs to be simple and easy to understand for developers of all 
calibres.  Hence, the less we need to say the better.


Khalid Belhajjame wrote:
> During the F2F meeting, there was a discussion in the second day 
> regarding “IVP of”. The definition that was suggested during the F2F can 
> be found in [1]. In my opinion, the definition of "IVP of" should be 
> simplified. Specifically, I would prefer a definition that states that 
> “IVP of” is an asserted relationship between two entity states. I list 
> in what follows the reasons:
> (i) In the definition of “IVP of” [1], the conditions on the properties 
> of the two entity states A and B (i.e., that the properties the entity 
> states share must have corresponding values, and that some mutable 
> properties of A correspond to some immutable properties of B), are not 
> enough in order to infer that B is an IVP of A. This is because there is 
> a third condition that is not included, because it is hard to formally 
> specify, viz. A and B are consistent.
> (ii) A consequence of (i), is that we will not be able to automatically 
> infer that an entity state B is an IVP of another entity state B. All we 
> can safely do, is identify cases in which an entity state B cannot be an 
> IVP of another entity state of A.
> (iii) Even if we find a means for formally specifying that two entity 
> states A and B are consistent, e.g., using assertions, it will be 
> difficult to use the definition of IVP of to make inference. This is 
> because the definition of IVP of requires correspondences between the 
> properties of two entity states to be specified. These correspondences 
> can be complex many-to-many mappings that may turn out to be hard to 
> encode using existing semantic web technologies.
> Thanks, khalid
Received on Tuesday, 12 July 2011 07:53:04 UTC

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