Metamath Proof Explorer


Theorem nfale2

Description: An inner existential quantifier's variable is bound. (Contributed by SN, 11-Feb-2026)

Ref Expression
Assertion nfale2 ⊢ Ⅎ x ∀ y ∃ x φ

Proof

Step Hyp Ref Expression
1 hbe1 ⊢ ∃ x φ → ∀ x ∃ x φ
2 1 nfalh ⊢ Ⅎ x ∀ y ∃ x φ