Number of units and number of copies

[cKlee]

Two properties might be missing:

Number of units - The number of the units an Item consits of.

$item holding:numberOfUnits "3"^^xsd:integer .

Number of copies - The number of identical copies an agent holds.

$item
    holding:heldBy $agent ;
    holding:numberOfCopies "2"^^xsd:integer .

@dini-ag-kim/bestandsdaten

[nichtich]

The latter is a ternary relationship that cannot be expressed this way in RDF:

$item
    holding:heldBy $agent1, $agent2 ;
    holding:numberOfCopies "2"^^xsd:integer ; # which agent?
    holding:numberOfCopies "5"^^xsd:integer ; # which agent?

The former might violate the Open World Assumption as well, but it's worth to discuss. What's the RDF property to relate an "item" and a "unit"?

[cKlee]

What's the RDF property to relate an "item" and a "unit"?

I think it is dct:hasPart?

[nichtich]

dct:hasPart can also relate items and other items, so what does the new term "unit" refer to? I'd not talk about units but items that are part of other items.

$doc a bibo:Document ; holding:exemplar $copy1 . $copy1 a frbr:Item ; dct:hasPart $page3ofcopy1 .

not sure whether this can already be derived (it should be)

$doc holding:narrowerExemplar $page3ofcopy1 .

The number of parts only makes sense with a qualifier, e.g. number of pages, of chapters, of frames, of articles, of issues etc. An item could have "units" of different kind, couldn't it?

By the way the general property dct:extent can be used to give the number of parts.

[cKlee]

$item holding:heldBy $agent1, $agent2 ; holding:numberOfCopies "2"^^xsd:integer ; # which agent? holding:numberOfCopies "5"^^xsd:integer ; # which agent?

How can this be possible? Two Agents holding one item?

[nichtich]

cardinality restrictions are not part of the ontology yet. Good point!