Composite relationship and 0..1 multiplicity

[Piotr Rzexniczak]

Can somebody explain me how the composite relationship and the 0..1 multiplicity can coexist together? Let's see at the attachment: EncapsulatedClassifier - Port relationship (from UML 2.1 spec):

EncapsulatedClassifier is a structured classifier

Port is a Property

Property is a part of StructuredClassifier

It means to me that Port can not exist without a EncapsulatedClassifier as its part

So - What the 0 in 0..1 multiplicity means? In my current understanding of this only 1 multiplicity would be correct...

[Ove Lindström]

I agree with you that is looks a bit strange.

The only explanation I can come up with is if we have all the Ports in a pool so that we can define all ports but not assign them to an EncapsulatedClassifyer. But it still looks strange.