http://purl.obolibrary.org/obo/IAO_0000412 "For external terms/classes, the ontology from which the term was imported"

What does 'external' mean, how should the ontology be referenced (e.g. IRI vs versionIRI) and what does 'imported' mean? Also, the def implies this is restricted to classes, why?

Is this intended as a functional property (can't be specified for APs in OWL2 but we could add something to IAO to state this)

How does this relate, if at all, to rdfs:isDefinedBy?

The use of 'imports' conflicts with owl:imports in cases where this property is used, e.g.:

http://www.ontobee.org/browser/rdf.php?o=OBI&iri=http://purl.obolibrary.org/obo/CL_0000236

obi.owl does not stand in an owl:imports to cl.owl, so this is confusing.

Tentative proposal:

We use rdfs:isDefinedBy to denote the authority for an OWLObject (fulfilling the need that is currently filled by using the ID space). We have a local restriction that this is functional (i.e. no class is "jointly owned"). We can also map the OBO-Format "namespace" tag (which is not an OWL/RDF namespace) to this property (somewhat awkward as historically there are 3 "namespaces" for GO).

If required, we have separate properties for clear semantics such as "axioms copied from" where we have axioms (logical and non-logical) copied from one ontology to another (as is the case for cl in obi)

Consider obsoleting this. A term is imported when it is not defined by the authority that is creating the ontology(into which it is being imported).

So the idea is that we instead use explicit rdfs:isDefinedBy axioms?