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Re: Is _this_ what is meant by "Entity"?

From: Graham Klyne <GK@ninebynine.org>
Date: Mon, 05 Sep 2011 10:01:44 +0100
Message-ID: <4E648FF8.10201@ninebynine.org>
To: public-prov-wg@w3.org
On 03/09/2011 14:35, Myers, Jim wrote:
> Luc may have a different perspective, but I think your description of e0 may not capture what's needed:
>
>>    entity(e0, [ type: "File", location: "/shared/crime.txt", creator: "Alice" ])
>
>> might be interpreted as asserting that the thing denoted by "e0" is a file whose
>> file system location is "/shared/crime.txt", and which was created by "Alice".
>
> e0 is a characterization of a file as a file-in-a-fixed-location - e0 is the file at location /shared/crime.txt. The thing - the file currently  at /shared/crime.txt is ambiguously defined in terms of time and processing - if I swap new content to /shared/crime.txt - has the thing moved or has it changed in place. For e0, its clear - e0 can't move. I could also have an entity with fixed content (whatever is at /shared/crime.txt now) which would have moved (or an entity representing the file with fixed location and content that would have ended/been used by the swap PE).
>
> Is this consistent with your interpretation? (With Luc's?) To me an entity is an asserted interpretation of how a thing is scoped with respect to time/processing...

I think it's consistent.  The content may change, but as far as e0 is concerned, 
all that has been constrained is its type, file system location, and creator 
(subject to the actual semantics of "type", "location" and "creator").

> The fact that a file was moved from location A to B can be asserted by asserting entities that characterize the movable file as file-in-location-A and file-in-location-B and asserting that file-in-location-B wasGeneratedBy a move PE that used file-in-location-A.

Er, I think I agree.  That is, if we have:

   entity(e0, [ type: "File", location: "/shared/crime.txt", creator: "Alice" ])

   entity(f0, [ type: "File", location: "/shared/crime2.txt", creator: "Alice" ])

Then it would be quite reasonable that there is a process execution that 
copies/moves e0 to generate f0.  Is that the sort of thing you mean?


> (If useful, one can also characterize the mobile file as well (perhaps as file-with-fixed-content) and talk about its provenance as well (the series of edits that created it from other fixed-content-files ignoring how those files might have been moved around) and even link the descriptions (via IVPof/complementOf).)

Like this?:

   entity(ef0, [ type: "File", creator: "Alice" ])

#g
--
Received on Monday, 5 September 2011 09:20:16 GMT

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