Metamath Proof Explorer


Theorem eumoi

Description: Uniqueness inferred from existential uniqueness. (Contributed by NM, 5-Apr-1995)

Ref Expression
Hypothesis eumoi.1 ∃! x φ
Assertion eumoi * x φ

Proof

Step Hyp Ref Expression
1 eumoi.1 ∃! x φ
2 eumo ∃! x φ * x φ
3 1 2 ax-mp * x φ