Metamath Proof Explorer


Theorem dfmo

Description: Simplify definition df-mo by removing its provable hypothesis. (Contributed by Wolf Lammen, 15-Feb-2026)

Ref Expression
Assertion dfmo ⊢ ∃* x φ ↔ ∃ y ∀ x φ → x = y

Proof

Step Hyp Ref Expression
1 mojust ⊢ ∃ y ∀ x φ → x = y ↔ ∃ z ∀ x φ → x = z
2 1 df-mo ⊢ ∃* x φ ↔ ∃ y ∀ x φ → x = y