Metamath Proof Explorer


Theorem brdom

Description: Dominance relation. (Contributed by NM, 15-Jun-1998)

Ref Expression
Hypothesis bren.1 B V
Assertion brdom A B f f : A 1-1 B

Proof

Step Hyp Ref Expression
1 bren.1 B V
2 brdomg B V A B f f : A 1-1 B
3 1 2 ax-mp A B f f : A 1-1 B