Metamath Proof Explorer


Theorem bj-alnnf2

Description: If a proposition holds, then it holds for all values of a given variable if and only if it does not depend on that variable. (Contributed by BJ, 28-Mar-2026)

Ref Expression
Assertion bj-alnnf2 ( 𝜑 → ( ∀ 𝑥 𝜑 ↔ Ⅎ' 𝑥 𝜑 ) )

Proof

Step Hyp Ref Expression
1 bj-alnnf ( ( 𝜑 → ∀ 𝑥 𝜑 ) ↔ ( 𝜑 → Ⅎ' 𝑥 𝜑 ) )
2 1 pm5.74ri ( 𝜑 → ( ∀ 𝑥 𝜑 ↔ Ⅎ' 𝑥 𝜑 ) )