fact: Definition cantor_bernstein_bij A B f g := let F := intersection (Zo (\Po A) (fun z => (forall t, inc t z -> inc (Vf g (Vf f t)) z) /\ sub (A -s Imf g) z)) in let h := fun x => Yo (inc x F) (Vf f x) (union (Vfi1 g x)) in Lf h A B.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)