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Re: PROV-ISSUE-8: defining generation in terms of `IVPT of'

From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Date: Fri, 10 Jun 2011 16:59:06 +0100
Message-ID: <EMEW3|3f2d9da73e3aed693fa0a11dacc81887n59GxB08L.Moreau|ecs.soton.ac.uk|4DF23F4A.50104@ecs.soton.ac.uk>
To: "Myers, Jim" <MYERSJ4@rpi.edu>
CC: public-prov-wg@w3c.org
Hi Jim
I think we are discussing two issues here.

1. You suggest that the egg is itself an IVPT.

    There are different ways of looking at this:
    a. I was saying that an egg was a thing (identified, and  typed 
according to an ontology)
        Then, it's a question of choice of a same ontology, or ontology 
refinement, a classical problem,
        which we will not solve here.

    b. We could say that there is in an alternate account, which 
describes the egg in terms of molecules.

    c.  Alternatively, we have IVPTs of IVPTs of IVPTs ...
         is there a base case? I fear we are going to reach quantum 
mechanics ...

2. You are commenting on the word modified.
      If I crack the egg,
        Y-> crack -> X
        Y and X are IVPTs of egg
        Y->X (we have a derivation)

      So looking at generation only, I feel it's OK to say the egg is 
modified, since we
     have now a new IVPT Y about the same egg.

So, could you maybe make some suggestions on how you would revise the 
definition?

Thanks,
Luc


On 06/10/2011 02:28 PM, Myers, Jim wrote:
>
>    
>> -----Original Message-----
>> From: Luc Moreau [mailto:L.Moreau@ecs.soton.ac.uk]
>> Sent: Friday, June 10, 2011 3:26 AM
>> To: Myers, Jim
>> Cc: public-prov-wg@w3c.org
>> Subject: Re: PROV-ISSUE-8: defining generation in terms of `IVPT of'
>>
>> Hi Jim,
>>
>> I had not seen your comment in line, my responses are also inline.
>>
>> On 10/06/11 02:28, Myers, Jim wrote:
>>      
>>> This would mean that a heating process modifies an egg to create a
>>>        
> warm egg,
>    
>> it does not transform a cold egg into a warm egg?
>>      
>>> Or do you mean both - a process execution can turn one thing into
>>>        
> another,
>    
>> these things can be considered IVPTs of a thing that participates in
>>      
> the process
>    
>> execution/ is modified by the process execution? And in an open world
>> assumption, a witness doesn't have to report the modified thing or can
>>      
> decline
>    
>> to identify/report either of things in IVPT roles depending on their
>>      
> ability to
>    
>> observe and the use case they wish to enable?
>>      
>>> ________________________________
>>>
>>> From: public-prov-wg-request@w3.org on behalf of Luc Moreau
>>> Sent: Thu 6/9/2011 6:44 PM
>>> To: Provenance Working Group WG
>>> Subject: PROV-ISSUE-8: defining generation in terms of `IVPT of'
>>>
>>>
>>>
>>> Hi all,
>>>
>>> - if a new thing is created, it is clear that we have a new IVPT of
>>> that thing
>>>
>>> if a chicken creates an egg is it just an IVPT of an egg?
>>>
>>>        
>> I would think the physical object is the egg.
>> I thought we had agreed that for a provenance purpose, we had to talk
>>      
> about
>    
>> an IVPT of that egg.
>>      
> But 'the egg' is also an IVPT of the stuff that goes into the cake - a
> temporary 'state' in which yolk and white are together and not
> mixed/chemically altered, etc.
>    
>>      
>>> - if the thing is modified, then it is a requirement that a new view
>>>        
> (IVPT) is
>    
>> generated ...
>>      
>>>          otherwise, it would still be a view that existed before
>>>
>>> can't I say the egg was heated without reporting its cold and warm
>>>        
> states? I.e.
>    
>> don't we want to be able to report that something was modified without
>>      
> having
>    
>> to report the IVPTs? A document was edited four times by different
>>      
> people but I
>    
>> don't wan't to/can't tell you what each wrote at each stage?
>>      
>>>        
>> These comments were made in the context of defining Generation of an
>>      
> IVPT.
>
> OK - but you said "if the thing is modified"... For generation, I would
> say the chicken participates in an egg laying process execution that
> generates an 'egg'. That 'egg' is an IVPT of the chemicals in it (which
> existed before). The 'egg' can also have further/more stateful IVPTs
> that are more useful for discussing heating, cracking, etc. The sense in
> which generation is special is that it is a derivation from things we
> don't consider logically an aspect/IVPT of something greater. I.e. the
> 'mass of egg-bound chemicals' in the chicken just changes its state to
> become the 'egg', nothing really appears or disappears (conservation of
> mass and energy). Unless/until a scientist wants to look at the
> potential for different processing of chemicals going into the egg
> versus those used to build the chicken's own body, 'mass of egg-bound
> chemicals' isn't something we'd usually think about, but it's a valid
> perspective and consistent with the view of an egg being generated (both
> views can be drawn on the same graph in the way I've been describing).
>
>    
>> The document was edited four times could be expressed by 4 process
>>      
> execution
>    
>> and something like opm:wasTriggeredBy in between.
>>
>>      
>>> - if the process execution was taking a long time to modify/create
>>>        
> the thing,
>    
>> there is only one
>>      
>>>      instant at which the (invariant!) IVPT appears
>>>
>>> I thnk we could define it that way, but if a cracking process takes
>>>        
> time, saying
>    
>> the cracked egg appears instantaneously basically means you want
>>      
> 'cracked egg'
>    
>> to be defined by some threshold - the cracked egg might become more
>>      
> cracked
>    
>> over time ) invariant only in that it is always above the threshold
>>      
> and the
>    
>> instance of the creation of the IVPT relationship occurs ata
>>      
> aspecific instant.
>    
>>>        
>> Yes, agreed.
>>
>>      
>>> - I think this captures well a stateful objects, where processes can
>>>        
> modify the
>    
>> object, resulting in
>>      
>>>      different IVPTs corresponding to the various states
>>>
>>> IVPTs are not a separate kind of thing and their invariance is
>>>        
> relative. If they
>    
>> are truly immutable sates/snapshopts, they can only exist for an
>>      
> instant because
>    
>> some part of the state of the thing (a part we may not care about such
>>      
> as age)
>    
>> will change immediately.
>>      
>>>        
>> I am not sure I agree, here. IVPTs are a view/perspective on a thing.
>>      
> Perhaps I should argue from the other direction - the notion of a thing
> is also a perspective/view. "eggs" don't exist - only temporary
> co-locations of particular molecules. Galton and Mizoguchi's paper
> argues that objects are defined by what processes you consider to be
> internal to and external to the object - if you change the set of
> processes you are concerned about, you describe the world using
> different objects. In this sense, eggs feel more 'real' because the set
> of processes we see happening frequently to them preserve aspects of
> their state, so egg as an IVPT is useful/predictive/etc.
>    
>> Alternative views asserted by other asserters may co-exit.
>> - it's a decaying egg
>> - it's a duck egg, not a hen egg
>> - it's a chocolate egg
>>
>>      
> I agree, so again from the other direction - I don't see why 'egg' is
> more real/more correct/more special than any of these, they're all
> IVPTs.
>
>    
>> It is a requirement of any specific perspective to be invariant.
>>      
> Invariant relative to a view in which only certain processes are of
> interest (are observable/reported?).
>
>    
>> So, it's not a snapshot of the global egg state, but it's a snapshot
>>      
> according to a
>    
>> view.
>>
>> An analogy would be several cameras pointing to a same egg.
>>   From one camera, the egg is still, no change occurring.
>>   From the other, we see a crack appearing.
>> So one asserter can describe change in a physical object, while
>>      
> another does not
>    
>> describe any change.
>> But it's the same egg.
>>      
> Right - those are two views of something. But that something is just
> another view - one camera sees a soup of chemicals that are swirling and
> mixing (slowly for an egg) while another sees one thing (the egg). Both
> of these are just IVPTs too. The chemical view is mutable by more
> processes than the egg view, but it is more persistent (it lasts longer
> because we've defined it in a way that the processes that can
> create/destroy it are less frequent).
>
> I know that thinking of everything as an IVPT is not necessarily
> intuitive, and that one can argue that it is just one way to model the
> world/a philosophy, but I think it is a model that has the right
> conceptual power to deal with the use cases we have (and the general set
> we can envision) while also being one that, in practice, will fade away
> - most people will agree that 'egg' and not 'mass of chemicals' is a
> more useful IVPT to talk about and we'll see 'eggs' used in cake baking
> and the world will mostly look like OPM (straight thing-execution-thing
> chains), but we'll still have the power to drop down and talk about
> cracking or go up and talk about conservation of mass when needed.
>
> I also don't know what a coherent alternative is that, once we add in
> all the features necessary to cover the use cases, we'll like better.
> There are certainly other ways to model - my question really is whether
> there are others that will end up being more intuitive once all the
> needed features are dropped in.
>
> -- Jim
>
>   Jim
>    
>> Luc
>>      
>>> What do you think?
>>>
>>>
>>>        
>> http://www.w3.org/2011/prov/wiki/ConceptGeneration#Definition_of_Gener
>>      
>>> ation_by_Luc
>>>
>>> Cheers,
>>> Luc
>>>
>>>
>>>        

-- 
Professor Luc Moreau
Electronics and Computer Science   tel:   +44 23 8059 4487
University of Southampton          fax:   +44 23 8059 2865
Southampton SO17 1BJ               email: l.moreau@ecs.soton.ac.uk
United Kingdom                     http://www.ecs.soton.ac.uk/~lavm
Received on Friday, 10 June 2011 15:59:42 GMT

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