`adms:Identifier` alignment

[jakubklimek]

Problem statement In the GeoDCAT-AP 2.0.0 usage of adms:Identifier, there are some differences with its usage in DCAT-AP 3.0. Specifically:

1. skos:notation is mandatory in DCAT-AP 3.0, but optional in GeoDCAT-AP 2.0.0

2. the range of skos:notation is defined as

   rdfs:Literal typed with the URI of one of the members of the DataCite Resource Identifier Scheme [DataCite-RIS]

   in GeoDCAT-AP

   1. here, it is unclear why the range rdfs:Literal was narrowed down to only those typed by the items from the DataCite Resource Identifier Scheme.
   2. It is in conflict with the usage note on other identifier which allows other identifier schemes as well:

      This property refers to a secondary identifier of the Dataset, such as MAST/ADS [MAST-ADS], [DataCite], [DOI], [EZID] or [W3ID].

Proposal Align with DCAT-AP 3.0, i.e. make skos:notation mandatory and lift the restriction of its range to rdfs:Literal without specifying a mandatory datatype

[jakubklimek]

Approved during the webinar.