Re: PROV-ISSUE-186: Section 5.2.1 (PROV-DM as on Nov 28) [prov-dm]

Hi Luc,
As you mentioned, this issue has been superseded and I am fine with closing
this issue.

Thanks.

Best,
Satya

On Wed, Dec 7, 2011 at 6:08 AM, Luc Moreau <L.Moreau@ecs.soton.ac.uk> wrote:

> Hi Satya,
>
> This discussion about identifier is now the remit of PROV-ISSUE-183.  Once
> PROV-ISSUE-183 is resolved,
> I think this one is also resolved.
>
> Further responses interleaved.
>
> On 12/07/2011 01:50 AM, Provenance Working Group Issue Tracker wrote:
>
>> PROV-ISSUE-186: Section 5.2.1 (PROV-DM as on Nov 28) [prov-dm]
>>
>> http://www.w3.org/2011/prov/**track/issues/186<http://www.w3.org/2011/prov/track/issues/186>
>>
>> Raised by: Satya Sahoo
>> On product: prov-dm
>>
>> Hi,
>> The following are my comments on Section 5.2.1 of the PROV-DM as on Nov
>> 28:
>>
>> Section 5.2.1:
>> 1. "entity record is a representation of an entity."
>>
>> Comment: So, we make provenance assertions about the entity or the entity
>> record? How is a provenance assertion about the entity differentiated from
>> an entity record?
>>
>>
>
> The entity is the thing and its situation in the world, the entity record
> is what we hold in a provenance record.
> We're making assertions about entities.
>
>> For example, is there is a difference between:
>> a) entity(e0, [ prov:type="File", ex:path="/shared/crime.txt",
>> ex:creator="Alice" ])
>> and
>> b) e0 has size 10KB on disk - this assertion clearly does not mean that
>> the entity record "entity(e0, [ prov:type="File",
>> ex:path="/shared/crime.txt", ex:creator="Alice" ])" has size 10KB! The
>> entity record, with about 80 characters, may have size 1KB on disk.
>> e0 is a representation of the entity (located at /shared/crime.txt and
>> created by Alice). In any knowledge representation approach and in
>> information systems, we always work with representation of the real world
>> thing and refer to these representations by an identifier. Clearly entity
>> and its records are two distinct information resources. How is fusing
>> entity and its record into single identifier relevant for modeling
>> provenance of entities?
>>
>> 2. "id: an identifier id identifying an entity; the identifier of the
>> entity record is defined to be the same as the identifier of the entity; "
>>
>>
>
>  Comment: If the id of entity and entity record are the same, then how can
>> two distinct set of assertions about the same entity exist?
>> If we use wasComplementOf Approach: We will create a new identifier
>> everytime we want to make an assertion about the same entity?
>> E.g. Harvard University was established in the 17th century.
>>      Harvard University was established in the year 1636.
>> will require two distinct identifiers for Harvard University?
>> Using wasComplementOf does not solve the problem since if there are
>> 100,000 assertions about Harvard University we will end creating 100,000
>> identifiers and will have to link them together using 100,000
>> wasComplementOf properties. This is clearly an overly complicated modeling
>> approach. More importantly, this goes against the Web architecture approach
>> of re-use identifiers instead of minting new ones (in this case clearly
>> avoidable):
>> > From the AWWW [1] :
>> a. Good practice: Avoiding URI aliases - "A URI owner SHOULD NOT
>> associate arbitrarily different URIs with the same resource."
>>
>> [1] http://www.w3.org/TR/2004/REC-**webarch-20041215/#uri-aliases<http://www.w3.org/TR/2004/REC-webarch-20041215/#uri-aliases>
>>
>>
>
> I don't think we do, do we?
>
>> 3. "If an asserter wishes to characterize an entity with the same
>> attribute-value pairs over several intervals, then they are required to
>> assert multiple entity records, each with its own identifier (so as to
>> allow potential dependencies between the various entity records to be
>> expressed)."
>>
>> Comment: If the entity has to be characterized with different
>> attribute-value pairs over same intervals, do they create distinct
>> identifiers?
>>
>>
>
> An example illustrating this case is covered in section 8 of the document.
>
> Luc
>
>> Thanks.
>>
>> Best,
>> Satya
>>
>>
>>
>>
>>
>
> --
> 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<http://www.ecs.soton.ac.uk/~lavm>
>
>
>