Comments of PROV-DM document (Section 2.1 and 3)

Hi all,
I have some review comments on Section 2.1 and Section 3 of the current
version of the conceptual document (these do not include typos/language and
related issues).

Section 2.1
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1. A characterized thing fixes some aspects of a thing and its situation in
the world, so that it becomes possible to express its provenance, and what
causes these specific aspects to be as such. An alternative characterized
thing may fix other aspects, and its provenance may be entirely different.

*Issue*: A "thing" may be characterized differently, that is viewed in
distinct ways, but they are still the same thing. Does the above statement
refer to the "same" thing characterized differently or distinct things? If
the above statement is referring to different characterization of the same
thing, how can their provenance be "entirely different"?

2. The provenance of these three characterized things will differ, and may
be along the follow lines:
a) the provenance of a report available at URL may include: the act of
publishing it and making it available at a given location, possibly under
some license and access control;
b) the provenance of the version of the report available there today may
include: the authorship of the specific content, and reference to imported
content;
c) the provenance of the report independent of where it is hosted over time
may include: the motivation for writing the report, the overall methodology
for producing it, and the broad team involved in it.

*Issue*: Not sure about the issue that is being illustrated/described here -
the three "characterized" things may be the same or different. In case they
are the same thing - Report A (version 1.0, only one version was ever
published) located at URL www.xyz.com/ReportA_V1.0 can be referred to
differently by individual applications according to their requirements:
simply as Report A, or as version 1.0 of Report A, or
www.xyz.com/ReportA_v1.0 - in this case provenance of the three different
characterization will be same.

Further, we can associate the provenance information for (b) with (a) also,
for example reference to imported content? Similarly for (c) and (b), (a),
for example the motivation to write the report or broad team involved. I am
confused regarding the criteria used to state the particular provenance
information can be associated with (a), (b), or (c).

In case they are referring to different things (different reports located at
same URL, different version of same report etc.), the provenance will be
different.

3. This specification assumes that a partial order exists between events.

*Issue*: Are we excluding overlapping events or events that are "contained"
in other events?

4. In our conceptualization of the world, punctual events, or events for
short, happen in the world, which mark changes in the world, in its
activities, and in its things.

*Issue*: This definition of event seems to be a specialization of a PE? What
are the distinguishing features (if any) of an event vis-a-vis PE?

*Section 3*
=====
1. The wasComplementOf relationship is used to denote that two entities
complement each other, in the sense that they each represent a partial, but
mutually compatible characterization of the same thing.

*Issue*: What does "entity" in the above statement refer to? How can two
entities refer to the same thing - assuming that entity is the term we
agreed to use for "thing"?

2. Qualifiers can be associated to relations, namely use and wasGeneratedBy,
in order to further characterise their nature. Role is a standard
qualifier.

*Issue*: Are qualifiers associated with relations only - they can be
associated with entities also to further "characterize" it (and thereby
create specialized entities)? What do we mean by "standard qualifier"?

2. Attributes, qualifiers, and annotation are the main extensibility points
in the model: individual interest groups are expected to extend PROV-DM by
introducing new sets of attributes, qualifiers, and annotations as needed to
address applications-specific provenance modelling requirements.

*Issue*: Since annotation have no prescribed meaning, how can they be used
to extend the model? What is the difference between attributes and
qualifiers? Qualifiers are standard mechanism for specialization (either
entities or relations) - new attributes may or may not be used to define
specialized entities or relations. For example, a new attribute stating that
a Toyota Corolla car hasMileage 100miles does not necessarily extend the
entity Toyota Corolla car?

Thanks.

Best,
Satya