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 ↔ ∃ 𝑦𝑥 ( 𝜑𝑥 = 𝑦 ) )

Proof

Step Hyp Ref Expression
1 mojust ( ∃ 𝑦𝑥 ( 𝜑𝑥 = 𝑦 ) ↔ ∃ 𝑧𝑥 ( 𝜑𝑥 = 𝑧 ) )
2 1 df-mo ( ∃* 𝑥 𝜑 ↔ ∃ 𝑦𝑥 ( 𝜑𝑥 = 𝑦 ) )