What's the name of that property...?

[helios]

...where if B is-an A, then List<B> is-a List<A>?

[S G H]

If List is something like std::list ... Is it a typedef? No idea.

[helios]

No, in terms of generic OOP concepts, not applied to any particular language.

[booradley60]

Maybe?
http://en.wikipedia.org/wiki/Covariance_and_contravariance_%28computer_science%29

[helios]

Covariance, that's the one. Thanks.