Re: PROV-ISSUE-321 (dgarijo): Instances of involvements can be expressed without a subclass. [Ontology]

On Mar 14, 2012, at 7:34 PM, Stephan Zednik wrote:

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> -----Original Message-----
> From: Provenance Working Group Issue Tracker [mailto:sysbot+tracker@w3.org] 
> Sent: Wednesday, March 14, 2012 6:37 PM
> To: public-prov-wg@w3.org
> Subject: PROV-ISSUE-321 (dgarijo): Instances of involvements can be expressed without a subclass. [Ontology]
> 
> PROV-ISSUE-321 (dgarijo): Instances of involvements can be expressed without a subclass. [Ontology]
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> http://www.w3.org/2011/prov/track/issues/321
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> Raised by: Luc Moreau
> On product: Ontology
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> The ontology allows for instances of involvements to be expressed, without specifying its subclass (Usage, Generation, etc). This is not aligned with the data model.
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> The only way to prevent this would be to define Involvement as a union class, which is not allowed in OWL2-RL.  This would also prevent users from extending Involvement directly, they would have to extend one of the subclasses.  I am not sure if we want Involvement itself to be an extension point in the ontology.
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> Also, I would say that this is not aligned with the PROV-N notation in DM.  The DM only defines PROV-N constructs for classes that would be leaves in the concept hierarchy; this effectively means the PROV-N construct hierarchy is flat - which is not something we are looking to replicate in the ontology.

Well, looking at the latest DM I wouldn't say the DM has ~no~ concept hierarchy, but I must admit I am not sure if the hierarchy has the same implications it would in OWL/RDF.

1) Element appears to be an abstract concept since there is no DM construct for it, so you can't assert it directly.
 
The only way to support this in the ontology would be to not have prov:Element in the ontology, or to make prov:Element a union class (and therefore break our OWL2-RL requirement).  Using a union class would make more sense if we want to use prov:Element as the domain of prov:hasAnnotation.

With either option, users would not be able to extend prov:Element since it wouldn't exist or would be a union class.  I am not sure we would want this anyway.

2) Agent is a specialization of Entity, but ramifications of this are not detailed 
- can an Activity use an Agent?
- can an Activity generate an Agent?
- can an Agent be derivedFrom another Agent? of an Entity?
- can an Agent be an alternateOf another Agent?  of an Entity?
- can an Agent be a specializationOf another Agent? of an Entity?

These are all implications of Agents also being Entities in OWL/RDF, but I am not sure if they are intended implications in the DM.

3) Relations are grouped in the document, but there is no clear hierarchy in DM constructs.  Relation, Activit-Entity Relation, Activity-Agent Relation, Entity-Entity Relation and Entity-Entity Relation are all abstract concepts.

I think this means the relation hierarchy in DM is flat.  

I believe a hierarchy was added in the ontology to both logically group in the ontology as they are in the DM document structure and to make property domains and ranges easier to specify.

--Stephan

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> --Stephan
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Received on Thursday, 15 March 2012 02:07:59 UTC