Metamath Proof Explorer


Theorem wl-nfae1

Description: Unlike nfae , this specialized theorem avoids ax-11 . (Contributed by Wolf Lammen, 26-Jun-2019)

Ref Expression
Assertion wl-nfae1 ⊢ Ⅎ x ∀ y y = x

Proof

Step Hyp Ref Expression
1 aecom ⊢ ∀ y y = x ↔ ∀ x x = y
2 nfa1 ⊢ Ⅎ x ∀ x x = y
3 1 2 nfxfr ⊢ Ⅎ x ∀ y y = x