Introduce NDRs for adding links to other vocabs

[nissimsan]

A number of UN/CEFACT terms are defined elsewhere. In order to "fit in", we should include NDRs which define for specific elements terms such as broaderThan, narrowerThan, equivalentProperty, equivalentClass, subClass, subProperty linking to external terms.

For example uncl1153:Bill_of_lading_number rdfs:subPropertyOf schema:identifier

See also https://github.com/w3c-ccg/traceability-vocab/issues/230

[nissimsan]

We probably want to support some or all of these references. To be continued.

[nissimsan]

Encouragement to please add comments here for further discussion...

[onthebreeze]

there are a few different ideas here.

• equivalence to external vocabularies. We can do that (e.g. unece "party" is equivalent to schema.org "organisation"
• meaningful specialisations of uncefact generic terms (eg "rail" is a type of "transportMeans"). There are potentially two sub-types of this
  • when there exists a standard uncefact codelist that enumerates the specialised types then our NDR can just say "make a subclass for each term in the codelist"
  • when there is no term for the specialisation (eg billofLadingNumber as subtype of identifer). this , as a technical project maybe doesnt have the authority to define new semantics. However maybe we can define a governance mechanism for such extensions to be proposed, reviewed, and accepted/rejected.

This really does boil down to a vocabulary governance process. I think we need to "show the way" with a more decentralised governance process

[nissimsan]

We will do this with english sentences in the section: https://github.com/uncefact/vocab/blob/main/docs/tech-spec.md#equivalence-vocabs