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Re: Definitions and provenance and invariance

From: Graham Klyne <GK@ninebynine.org>
Date: Mon, 20 Jun 2011 11:22:41 +0100
Message-ID: <4DFF1F71.9000705@ninebynine.org>
To: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
CC: public-prov-wg@w3.org
It seems we understand the phrase "integral to identity" somewhat differently, 
so that's a different reason not use it as part of the definitions of "things" 
and "invariant views".  The more you say, the more room there is for 
disagreement ...

#g
--

Luc Moreau wrote:
> Hi Simon and Graham,
> 
> I added a response to Graham's comment on invariant property and identity.
> See http://www.w3.org/2011/prov/wiki/ConceptInvariantViewOnThing#Comments
> 
> Cheers,
> Luc
> 
> On 06/19/2011 12:18 PM, Simon Miles wrote:
>> Graham,
>>
>> OK, thanks for the clarification. I agree with your point, and am also
>> sympathetic to your discomfort with everything invariant being
>> "integral to identity".
>>
>> Thanks,
>> Simon
>>
>>
>> On 17 June 2011 23:00, Graham Klyne<GK@ninebynine.org>  wrote:
>>   
>>> Simon Miles wrote:
>>>     
>>>> Graham, Stian, all,
>>>>
>>>> I might be confused, but this seems a more complex model than the one
>>>> proposed by Jim and Luc.  Why do we need to both a Dynamic Resource
>>>> and a View Resource?  I can't see any meaningful difference between
>>>> them either in Graham's definition or Stian's (helpful) concrete
>>>> example.  What is the point of saying anything about a mutable
>>>> property, e.g. "content of DynamicResource i0", when any assertion of
>>>> a mutable property's value will not always hold anyway?
>>>>        
>>> Speaking for myself... I used the terms "Dynamic" and "View" as 
>>> labels to
>>> distinguish their roles in the structure given.  I would not choose 
>>> to model
>>> them as different types.
>>>
>>> My point, expressed in terms of Stian's example, is that the notion 
>>> we have been
>>> calling IVP is present in the viewOf relation rather than inherent in 
>>> the
>>> resources themselves.  This was my point, which I think is also at 
>>> the heart of
>>> the proposal by Jim and Luc.
>>>
>>> I happen to think that the definition as proposed in the wiki at
>>> http://www.w3.org/2011/prov/wiki/ConceptInvariantViewOnThing#ACCEPTED_at_teleconference_2011-06-16 
>>>
>>> is over-specified (I've added some comments there).  But having 
>>> expressed that
>>> reservation, I'm content to let them stand pro tem for the purposes 
>>> of discussion.
>>>
>>> #g
>>> -- 
>>>
>>>
>>>     
>>>> On 16 June 2011 15:39, Stian Soiland-Reyes
>>>> <soiland-reyes@cs.manchester.ac.uk>  wrote:
>>>>       
>>>>> On Tue, Jun 14, 2011 at 12:09, Graham Klyne<GK@ninebynine.org>  wrote:
>>>>>
>>>>>         
>>>>>> Suppose that the "Dynamic resource has a number of different 
>>>>>> observable
>>>>>> properties, some of which do not change over time, and others 
>>>>>> which do.
>>>>>>   Then the View resource would be a resource for with a similar 
>>>>>> set of
>>>>>> properties such that do not change over time, but correspond to 
>>>>>> the dynamic
>>>>>> resource properties at a given time (including properties that do 
>>>>>> not change
>>>>>> over time).  If the Dynamic resource does not change over time, 
>>>>>> then it may
>>>>>> also serve as its own view resource:  the has view property can be
>>>>>> reflexive.
>>>>>>
>>>>>> The provenance resource is an assertion about the properties of 
>>>>>> the view
>>>>>> resource.  I believe the key requirement that we try to capture is 
>>>>>> that the
>>>>>> properties about which the provenance resource makes assertions are
>>>>>> invariant - there is no assertion in the provenance resource which 
>>>>>> is not
>>>>>> always true of the view resource.
>>>>>>            
>>>>> This is a very beautifully simple model which I think we should keep
>>>>> in mind before digging too much into the exciting discussions.
>>>>>
>>>>>
>>>>>
>>>>> "simplified" for the File example:
>>>>>
>>>>>
>>>>> :i0 a :DynamicResource ;
>>>>>   :name "/home/towns.txt" ;
>>>>>   :content [ :bytes "" ] ;
>>>>>   :creator :Alice .
>>>>>
>>>>>
>>>>> :i0View a :ViewResource ;
>>>>>    :viewOf :i0 ;
>>>>>    :name "/home/towns.txt" ;
>>>>>    :creator :Alice .
>>>>>
>>>>>
>>>>> # Metadata stored in filesystem
>>>>> :i0Provenance a :ProvenanceResource ;
>>>>>    :provenanceOf :i0View ;
>>>>>    :account :FileSystem ;
>>>>>    :processes (
>>>>>       [  :agent :Alice ;
>>>>>          :location :server1 ;
>>>>>          :process :fileCreation ;
>>>>>          :time "2011-06-15 18:00:01 UTC"  ]
>>>>>     ) .
>>>>>
>>>>> # however the log file claims the file was created on her workstation
>>>>> (not server), and 1 second later (clocks out of sync?)
>>>>>
>>>>> :i0Provenance2 a :ProvenanceResource ;
>>>>>    :provenanceOf :i0View ;
>>>>>    :account :ServerLogFile ;
>>>>>    :processes (
>>>>>       [  :agent :Alice ;
>>>>>          :location :AliceWorkstation;
>>>>>          :process :fileCreation ;
>>>>>          :time "2011-06-15 18:00:02 UTC"  ]
>>>>>     ) .
>>>>>
>>>>>
>>>>>
>>>>> ### New graph - Content changed
>>>>>
>>>>> :i0 a :DynamicResource ;
>>>>>   :content [ :bytes "New York\nLos Angeles\n"  ] ;
>>>>>   :name "/home/towns.txt" ;
>>>>>   :creator :Alice ;
>>>>>   :readBy (:Alice :Bob :Charles :David)
>>>>>
>>>>>
>>>>> :i2 a :ViewResource ;
>>>>>   :viewOf :i0 ;
>>>>>   :name "/home/towns.txt" ;
>>>>>   :creator :Alice ;
>>>>>   :content [ :bytes "New York\nLos Angeles\n"  ] .
>>>>>
>>>>> :i2Provenance a :ProvenanceResource ;
>>>>>   :provenanceOf :i2 ;
>>>>>    :account :FileSystem ;
>>>>>    :processes (
>>>>>       [  :agent :Alice ;
>>>>>          :location :server1 ;
>>>>>          :process :fileCreation ;
>>>>>          :time "2011-06-15 18:00:03 UTC"  ]
>>>>> # Lost as :FileSystem metadata only keeps last-modified
>>>>> #     [   :agent :Alice ;
>>>>> #         :location :server1 ;
>>>>> #         :process :fileWrite ;
>>>>> #         :time "2011-06-15 18:00:03 UTC"  ]
>>>>>      [
>>>>>          #  :agent :Bob;  - not recorded as only owner/creator is kept
>>>>>          :location :server1 ;
>>>>>          :process :fileWrite ;
>>>>>          :time "2011-06-15 18:14:12 UTC"  ]
>>>>>     ) .
>>>>>
>>>>>
>>>>> So say there are additional mutable properties such as :readBy above -
>>>>> would you consider those propagating into the view as mutable
>>>>> properties? There could be another view over :i2 for the file before
>>>>> it was read by Charles, where :readBy is an immutable property.
>>>>>
>>>>> The example graph above does not distinguish between mutable and
>>>>> immutable properties - perhaps we shouldn't as they could be difficult
>>>>> to find, identify and measure.
>>>>>
>>>>> Here :readBy is not kept by neither the log file or file system and is
>>>>> a kind of conceptual property - it could be discovered by simply
>>>>> asking everyone who could have read it, or inferred from traced file
>>>>> usage, like if its sent in an email.
>>>>>
>>>>> -- 
>>>>> Stian Soiland-Reyes, myGrid team
>>>>> School of Computer Science
>>>>> The University of Manchester
>>>>>
>>>>>
>>>>> ______________________________________________________________________
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>>>>> ______________________________________________________________________
>>>>>
>>>>>          
>>>>
>>>>
>>>>        
>>>
>>> ______________________________________________________________________
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>>>
>>>      
>>
>>
>>    
> 
Received on Monday, 20 June 2011 11:44:12 GMT

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