RDF: using containers (bags?)?

[sanjayankur31]

Hi folks,

I've just added functionality to pyNeuroML to create annotations for NeuroML (and OMEX) files so that we can generate OMEX archives that contain the metadata biosimulations suggests/requires. While looking through the various docs, I see that in the Biosimulations docs, the example does not use any RDF containers at all. The snippet has:

<bqmodel:is>
      <rdf:Description>
        <dc:identifier rdf:resource="http://identifiers.org/biomodels.db:BIOMD0000000297"/>
        <rdfs:label>biomodels.db:BIOMD0000000297</rdfs:label>
      </rdf:Description>
    </bqmodel:is>

    <bqmodel:is>
      <rdf:Description>
        <dc:identifier rdf:resource="http://identifiers.org/jws:ciliberto"/>
        <rdfs:label>jws:ciliberto</rdfs:label>
      </rdf:Description>
    </bqmodel:is>

However, when looking at the COMBINE specs, I see that bags are used, for example:

<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
        xmlns:bqmodel="http://biomodels.net/model-qualifiers/">
  <rdf:Description rdf:about="#_000001">
    <bqmodel:is>
       <rdf:Bag>
        <rdf:li rdf:resource="https://identifiers.org/biomodels.db/BIOMD0000000004" />
       </rdf:Bag>
    </bqmodel:is>
    <bqmodel:isDescribedBy>
       <rdf:Bag>
        <rdf:li rdf:resource="https://identifiers.org/pubmed/1833774" />
       </rdf:Bag>
    </bqmodel:isDescribedBy>
  </rdf:Description>
</rdf:RDF>

Are bags compulsory, or optional? Should we or should we not use them?