= '''Discussion: Part/whole relations and ISO 15926-2''' =
This page is intended for a particular example given in ISO 15926-2, page 102, where part/whole relations are discussed.

Of particular difficulty is the fact that the diagram illustrating the discussion seems to confuse the notion of entity type with that of a defined class or relationship. In particular, the name ''assembly of individual'' is given as the name of a relation, even though this also names one of the most important entity types for relations.[[BR]][[BR]]The following graph is intended as an attempted reconstruction of the mentioned graphic. More discussion will follow, in the hope that confusion can be laid to rest.

{{{
#!LatexEquation
\TemplateDiagram{
    % column 1
    !c{WandI}{whole \& individual}{Role and Domain}
    (
    [d(1.5)]
    !c{6ofM8}{6 of M8 bolts}{Role and Domain}
    [d]
    !c{my6ofM8}{\#my 6 of M8 bolts}{Physical Object}
    )
    % column 2
    (
    [r]
    !t{corws_a}{CO Relationship with Signature}{assembly of individual}
%%     ( % detour for an additional entity type
%%       [d(.5)r(.4)]
%%       !e{ai}{Assembly of Individual}
%%       !l{corws_a}{ai}{}{}
%%       )
    [d(1.5)]
    !t{corws_6M8_a}{CO Relationship with Signature}{6 M8 bolt assembly}
    [d]
    !q{or}{Other Relationship}
    )
    % column 3
    (
    [rr]
    !c{PandI}{part \& individual}{Role and Domain}
    [d(1.5)]
    !c{PandM8b}{Part \& M8 Bolt}{Role and Domain}
    [d]
    !c{1}{\#1}{Physical Object}
    )
    % subclass arrows
    (
    !b{WandI}{6ofM8}
    !b{corws_a}{corws_6M8_a}
    !b{PandI}{PandM8b}
    )
    % membership arrows
    (
    !m{6ofM8}{my6ofM8}
    !m{corws_6M8_a}{or}
    !m{PandM8b}{1}
    )
    % relation symbols tied to boxes, top -- bottom
    (
    !s{corws_a}{WandI}{CO End 2}{PandI}{CO End 1}
    !s{corws_6M8_a}{6ofM8}{CO End 2}{PandM8b}{CO End 1}
    !s{or}{my6ofM8}{End 2}{1}{End 1}
    )
    % cardinality symbols tied to central corws
    (
    [d(1)r(0.3)]
    !c{card01}{0:1}{Cardinality}
    )
    (
    [d(1)r(1.7)]
    !c{card66}{6:6}{Cardinality}
    )
%%     (!l{corws_6M8_a}{card01}{End 2 Cardinality}{.5})
%%     (!l{corws_6M8_a}{card66}{End 1 Cardinality}{.3})
    (!s{corws_6M8_a}{card01}{End 2 Cardinality}{card66}{End 1 Cardinality}
  }
}}}
Suggestions:

 * The ''other relationship'' instance should have an (additional) entity type ''assembly of individual''
 * The relation which is called "assembly of individual" (overusing the name, clearly) should have an additional entity type ''class of assembly of individual''
 * Perhaps the graph, as given in ISO 15926-2, is confusing only because the text is at the point in question ''only'' intending to make a point about assignment of ''cardinality constraints''. Indeed, the section header is called precisely "Cardinality constraints".