Questions about listing equivalent things

[Steve Vestal <st...@adventiumlabs.com>]

There is a method OntClass#listEquivalentClasses that returns an extended
iterator.  There is no corresponding method for an Individual, e.g. no
Individual#listEquivalentIndividuals.  There is a method
OntResource#listSameAs.

In a test (Jena 3.17), classes that had been declared equivalent were returned
by OntClass#listEquivalentClasses but not by OntResource#listSameAs; and
individuals that had been declared equivalent were returned by
OntResource#listSameAs.  Is that expected, OntResource#listSameAs does not
list equivalent OntClasses?

There is an OntProperty#listEquivalentProperties.  Will this behave similarly
to listEquivalentClasses, i.e., not listed by listSameAs but listed by
listEquivalentProperties?  So is OntResource#listSameAs essentially a proxy
for an Individual#listEquivalentIndividuals method?

The Javadoc for OntResource#listSameAs says this will list things "declared to
be" the same.  What about things that are not declared to be equivalent but
are inferred to be equivalent?  Or does this really mean all equivalent
things?

Where punning is present, will each of these iterators return something if it
has that facet, e.g., if a URI is punned as both a class and an individual,
then it will be listed by both OntClass#listEquivalentClasses and
OntResource@listSameAs (a.k.a. the proxy
Individual#listEquivalentIndividuals)?

Re: Questions about listing equivalent things

[Lorenz Buehmann <bu...@informatik.uni-leipzig.de>]

That naming matches exactly the OWL language. in OWL classes are 
declared logically equivalent via owl:equivalentClass and individuals 
are denoted as the same entity via owl:sameAs

And "things" are not classes but real world entities that have an identity.

I doubt you'll get a hint for punning, listSameAs will still only return 
the owl:sameAs (and inferences based owl:sameAs) axioms. Same for 
classes, only if the URI is used as class in asserted (or inferred if 
the reasoner is capable to this inference) it will return the URI in 
listEquivalentClasses

On 02.10.21 23:07, Steve Vestal wrote:
> There is a method OntClass#listEquivalentClasses that returns an 
> extended iterator.  There is no corresponding method for an 
> Individual, e.g. no Individual#listEquivalentIndividuals.  There is a 
> method OntResource#listSameAs.
>
> In a test (Jena 3.17), classes that had been declared equivalent were 
> returned by OntClass#listEquivalentClasses but not by 
> OntResource#listSameAs; and individuals that had been declared 
> equivalent were returned by OntResource#listSameAs.  Is that expected, 
> OntResource#listSameAs does not list equivalent OntClasses?
>
> There is an OntProperty#listEquivalentProperties.  Will this behave 
> similarly to listEquivalentClasses, i.e., not listed by listSameAs but 
> listed by listEquivalentProperties?  So is OntResource#listSameAs 
> essentially a proxy for an Individual#listEquivalentIndividuals method?
>
> The Javadoc for OntResource#listSameAs says this will list things 
> "declared to be" the same.  What about things that are not declared to 
> be equivalent but are inferred to be equivalent?  Or does this really 
> mean all equivalent things?
>
> Where punning is present, will each of these iterators return 
> something if it has that facet, e.g., if a URI is punned as both a 
> class and an individual, then it will be listed by both 
> OntClass#listEquivalentClasses and OntResource@listSameAs (a.k.a. the 
> proxy Individual#listEquivalentIndividuals)?
>
>