Metamath Proof Explorer


Theorem euop2

Description: Transfer existential uniqueness to second member of an ordered pair. (Contributed by NM, 10-Apr-2004)

Ref Expression
Hypothesis euop2.1 ⊢ A ∈ V
Assertion euop2 ⊢ ∃! x ∃ y x = A y ∧ φ ↔ ∃! y φ

Proof

Step Hyp Ref Expression
1 euop2.1 ⊢ A ∈ V
2 opex ⊢ A y ∈ V
3 1 moop2 ⊢ ∃* y x = A y
4 2 3 euxfr2w ⊢ ∃! x ∃ y x = A y ∧ φ ↔ ∃! y φ