Hi Luc,
We were not able to reach an agreement on how ProvenanceContainer is not a
specialized type of Entity during our ontology call on Monday due to time
constraints.
To help better understand the differences and similarities, I copied the two
definition from PROV-DM to two documents and tried to compare them
side-by-side. The following are the two definitions:
===Entity====
In PROV-DM, an entity expression is a representation of an identifiable
characterized thing.
===ProvenanceContainer===
A provenance container is a house-keeping construct of PROV-DM, also capable
of bundling PROV-DM expressions. A provenance container is not an
expression, but can be exploited to return all the provenance assertions in
response to a request for the provenance of something ([PROV-PAQ]).
According to the two definitions, a provenance container can be an
"identifiable characterized thing" (not being an expression is not a
conceptual constraint). Also, the ability to return all provenance
assertions in response can be applied to an Agent also - similar to a
software agent returning the current stock market quotes.
Further, if an Entity "contains" provenance assertions it can still be an
"identifiable characterized thing" thereby satisfying our current definition
of Entity.
During our ontology telcon today Paolo explained that the primary difference
between Entity and Provenance Container is that Provenance Container can
"contain" provenance assertions while Entity are assumed not to contain
assertions. But, this seems to be an application-specific requirement.
For example, for a person writing a 3-page letter the three pages will be
instances of Entity and the envelope containing the three pages will be a
container. But for the postal service personnel, who deal with thousands of
envelopes per day, the envelope is an Entity (and a sack for transporting
the envelopes will be a container).
Hence, I believe the difference between what thing is a ProvenanceContainer
or an Entity is an application-specific perspective/requirement and there is
no fundamental difference between the two terms - except that Provenance
terms seems to be a specialized form an Entity in the sense that Provenance
Container contains provenance assertions, while an Entity may or may
notcontain provenance assertions.
Paolo suggested that we should bring up this issue to the WG mailing list -
hence I am cc'ing the mailing list also.
Thanks.
Best,
Satya
On Wed, Sep 28, 2011 at 3:58 AM, Luc Moreau <L.Moreau@ecs.soton.ac.uk>wrote:
> **
> Hi,
> I thought we had already discussed this, but I see location as subtype of
> entity.
> Same issue as with provenance container. This is not a subtype of entity.
>
> 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
>
>