a many$-$to$-$many relationship type in which one of the participating entity types is a weak

entity type;

$($b$)$ a many$-$to$-$many relationship type in which one of the participants is another relationship type

$($via an aggregation$)$;

$($c$)$ a subclass$/$subtype $($in a specialization$)$ that has a one$-$to$-$many relationship type with another

entity type;

$($d$)$ a total category that has another category as one of its superclasses$/$supertypes$.$