My understanding is that, in UML class diagrams, inheritance is a particular kind of association.
An association can have a multiplicity.
However, it seems that inheritance is never represented with a multiplicity.
Why?
Is it because the multiplicity is always 1..1
and 0..1
(example below)?
inheritance is a particular kind of association
This is a fundamental misunderstanding. Generalization (aka inheritance) is a particular kind of relationship but it is not an association.
Thus there is no multiplicity for it. Also as already mentioned it would make no sense to have one.
Generalization is on a class level. If a class B is a specialized class of class A, then all elements that are of type B are at the same time also of type A.