[NLP2RDF] NIF: mandatory properties and types

[Martín Rezk]

Dear all,
            I am new in the project, so I have been asking Sebastian
several question about the NIF standard, in particular, about  the
mandatory properties in NIF and their domain and range.
He asked me to switch to the mailing-list, so here I am, nice to meet you all.
In the last email, Sebastian, you told me that the only mandatory
property (including the SSO?) is referenceContext. Question: Can an
object have as referenceContext itself?
In page 6, in your EKAW paper, you have a 7 lines example. In such
example the first triple defines the whole document (offset_0_26546)
and it is not defined for the  (functional?) object property
referenceContext.
Instead, it is defined for the data property str:occursIn. In such
scenario, what does NIF require?  should offset_0_2654 have itself as
referenceContext? Should referenceContext not be mandatory in that
case?

Regarding the answer from the Pellet forum,  you told me that you will
not add axioms to prevent the wrong usage of OWL.
However, I think it would be interesting to give an optional simple
set of axioms that can be used to check the correctness of the
ontology.
Some of them could be

1) referenceContext is functional and mandatory.
2) There can not be cycles in the property referenceContext. That is,
it should disallow things like: A has as reference context B, and B
has as reference context A.
3)  If the class str:Nothing is meant to be bottom (from the logic
point of view), then the class str:Nothing should be empty.

Best wishes,

Martin Rezk.-