For concepts reified statements in XML, use IDs

[nicholascar]

ref:

• https://www.oreilly.com/library/view/practical-rdf/0596002637/ch04.html
• https://www.w3.org/TR/rdf-syntax-grammar/#section-Syntax-ID-xml-base

Currently XML uses a fromat like this:

<rdf:Statement rdf:about="http://vocab.nerc.ac.uk/collection/A05/current/EV_OXY/#I1391840">
    <prov:has_provenance rdf:resource="http://vocab.nerc.ac.uk/mapping/I/1391840/"/>
    <rdf:subject rdf:resource="http://vocab.nerc.ac.uk/collection/A05/current/EV_OXY/"/>
    <rdf:object rdf:resource="http://vocab.nerc.ac.uk/collection/P01/current/DOXYSCKG/"/>
    <rdf:predicate rdf:resource="http://www.w3.org/2004/02/skos/core#narrower"/>
</rdf:Statement>

should be:

<rdf:Description rdf:about="#I1391840">
    <prov:has_provenance rdf:resource="http://vocab.nerc.ac.uk/mapping/I/1391840/"/>
</rdf:Description>