add rdfs:isDefinedBy

[VladimirAlexiev]

Each ontology term should have rdfs:isDefinedBy to the ontology node.
This allows sem.web crawlers that stumble upon a CIM term, to discover the whole CIM ontology.

#5 is a soft blocker for this:

• We could add multiple values for each term
• But this is untypical usage
• It may lead to a crawler fetching the same ontology multiple times, but I think the risk is low since the crawler should keep a queue of ontologies to be fetched (or already fetched) in any case.

Note: https://github.com/Sveino/Inst4CIM-KG/blob/develop/archive/PROF-AP-CIM_v15July2020/PROF-CIM-Vocabulary.rdf has some related discussion:

Known Issue:
	Need to clearify is we shall have both domain and isDefinedBy.
	Added <rdfs:isDefinedBy rdf:resource="[class]"/>   to the object properties

[Sveino]

I am happy to add rdfs:isDefinedBy but should we also use rdfs:domain?

[VladimirAlexiev]

• We already have rdfs:domain and it means "this prop is defined on that class"
• rdfs:isDefinedBy means "this term (class or prop) is defined by that ontology"
  This is not an easy task, since some terms are defined by 20 ontologies.
  It only makes sense to do this after "ontology modularization" (now described at Duplication Between Ontologies #5 (comment))

[Sveino]

rdfs:isDefinedBy should then be equivalent to cims:belongsToCategory
I agree that this only make sense to do after "ontology modularization".