Re: Problems with Example 2 and 4 in https://www.w3.org/TR/2013/REC-prov-o-20130430

Dear Nicolas,

I'm sure others on this list will have more apposite responses, but as far as I am aware it was an intentional design decision NOT to make entity and agent disjoint (and similarly, NOT to make activity and agent disjoint).  Only entity and activity are disjoint.  The paper "The rationale of PROV" [1] explains that the group decided to minimize the number of disjointness constraints (requirement GE1), and later explains that activities and entities are disjoint (requirement VI7) but agents are allowed to be entities or activities (requirements VI3, VI4).  I am not sure whether this decision is explained explicitly in the PROV-O recommendation itself, but you can also see this recorded, for example, in the (non-normative) semantics document [2]:

> 3.2.3 Agents
> 
> An agent is an object that can act, by controlling, starting, ending, or participating in activities. An agent is something that bears some form of responsibility for an activity taking place, for the existence of an entity, or for another agent's activity. Agents can act on behalf of   other agents. An agent may be a particular type of entity or activity; an agent cannot be both entity and activity because the sets of entities and activities are disjoint.
> 

Thus, a heuristic that assumes that classes that have no common subclasses ought to have been declared disjoint, would not provide good advice in this case.

--James

[1] Luc Moreau, Paul Groth, James Cheney, Timothy Lebo, Simon Miles: The rationale of PROV. J. Web Semant. 35: 235-257 (2015)
[2] https://www.w3.org/TR/prov-sem/

> On Aug 2, 2021, at 11:23 PM, Rouquette, Nicolas F (US 319K) <nicolas.f.rouquette@jpl.nasa.gov> wrote:
> 
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> I have encoded the complete Prov-O ontology from the specification (https://www.w3.org/TR/2013/REC-prov-o-20130430 <https://www.w3.org/TR/2013/REC-prov-o-20130430>) using our Ontological Modeling Language, OML (http://www.opencaesar.io/oml/ <http://www.opencaesar.io/oml/>) that we created to facilitate ontology authoring for humans by automating the process of calculating disjointness axioms according to a simple policy: if two classes have no common specialization in the scope of a set of ontologies, then they are asserted to be disjoint in that scope. Applying this policy to an OML vocabulary of Prov-O helped identify two problems:
> In Example 2: https://github.com/opencaesar/provenance-vocabularies#example-2 <https://github.com/opencaesar/provenance-vocabularies#example-2>
> In Example 4: https://github.com/opencaesar/provenance-vocabularies#example-4 <https://github.com/opencaesar/provenance-vocabularies#example-4>
>  
> I understand that the working group that developed the provenance ontology has long been dismantled; however, I believe that it would be helpful to fix these problems as the examples convey a subtly incorrect idea about the domain/ranges of the properties involved.
>  
> Nicolas F. Rouquette
> Principal Computer Scientist
> Jet Propulsion Laboratory, California Institute of Technology M/S 301-490, 4800 Oak Grove Dr, Pasadena, CA 91189, USA
> email: nicolas.f.rouquette@jpl.nasa.gov <mailto:nicolas.f.rouquette@jpl.nasa.gov>
> phone: +1 (818) 354-9600
> cell: +1 (626) 639-5282