W3C home > Mailing lists > Public > public-prov-wg@w3.org > January 2012

Re: PROV-O call summary

From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Date: Thu, 5 Jan 2012 06:55:34 +0000
To: Timothy Lebo <lebot@rpi.edu>
CC: Provenance Working Group WG <public-prov-wg@w3.org>
Message-ID: <EMEW3|e63dbd082fdbf7ced703d1ff08f758cco046yx08L.Moreau|ecs.soton.ac.uk|876D08A4-9537-47AD-B7AA-14D3A7655F8C@ecs.soton.ac.uk>
Hi Tim, comments interleaved.

Professor Luc Moreau
Electronics and Computer Science
University of Southampton 
Southampton SO17 1BJ
United Kingdom

On 5 Jan 2012, at 02:16, "Timothy Lebo" <lebot@rpi.edu> wrote:

> Hi Luc,
> 
> Thanks for looking through our notes.
> 
> On Jan 4, 2012, at 6:14 PM, Luc Moreau wrote:
> 
>> Hi Tim,
>> 
>> Can you clarify what you intent with "prov:follows and prov:precedes properties missing".
> 
> prov:follows a owl:ObjectProperty; rdfs:domain time:Instant; rdfs:range time:Instant .
> similar for precedes.
> (and I need to raise an issue to ask for "equals")

It's strange. In prov-dm, we make the case for events because two different events could occur at the same time.  Follows and precedes are defined between events, but you modelled them as properties between instants.  It seems conflicting.  They should be properties between events (which may be known to exist but not the instant they map to).

> 
>> 
>> Follows and precedes are not part of the data model in the sense that they cannot be asserted by asserters. 
> 
> Cannot or generally would not?

They are not provenance record. So they can't be asserted or inferred as provenance records.



> Can they be inferred?


Not as prov record.  Ordering Constraints are implied by provenance records. To me, it is an open question as to whether this is actually useful to express these constraints in rdf.


> If so, then some RDF predicate is required to state the axiom and the result of applying the axiom.
> Also, what can be inferred can be directly asserted. Why the distinction?

Why? Because they are not provenance records. They are general constraints that must be satisfied.  I think there was also a desire to be "generous" and to allow for provenance records that break constraints. This would give us an indication of whether the records can be trusted or not.


> 
>> 
>> However derived ordering constraints must be satisfied for prov records.
>> 
>> It may be (or not) useful to be able to express these constraints in rdf, and therefore an ontological definition could make sense.  But it's not the prov-o ontology, it's in prov-o-constraints,
> 
> I don't see why a strong distinction between prov-o ontology and prov-o constraints needs to be made, other than that the group should settle the vocabulary and structure before tackling the more contentious axioms. By the time they are both done, I see them as two parts of a whole.
> 
>> or whatever ontology extending prov-o.
> 
> Seems a bit odd that associations among Events would be in an extension, when they are fundamental to DM.

Do you actually model events? Is there a class event? 


I am arguing for layering here: prov-dm records (essentially syntactic), ordering constraints(event interpretation), structural constraints.

> 
> Regards,
> Tim
> 
Luc
> 
>> 
>> 
>> Professor Luc Moreau
>> Electronics and Computer Science
>> University of Southampton 
>> Southampton SO17 1BJ
>> United Kingdom
>> 
>> On 4 Jan 2012, at 22:44, "Timothy Lebo" <lebot@rpi.edu> wrote:
>> 
>>> prov-wg,
>>> 
>>> The PROV-O team met today to review a list of topics where PROV-O is out of sync with PROV-DM.
>>> 
>>> The summary and notes are at http://www.w3.org/2011/prov/wiki/PIL_OWL_Ontology_Meeting_2012-01-04#Summary
>>> 
>>> Regards,
>>> Tim
>>> 
>>> 
>> 
>> 
> 
Received on Thursday, 5 January 2012 06:56:36 UTC

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