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