Metamath Proof Explorer


Theorem naecoms-o

Description: A commutation rule for distinct variable specifiers. Version of naecoms using ax-c11 . (Contributed by NM, 2-Jan-2002) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Hypothesis nalequcoms-o.1 ( ¬ ∀ 𝑥 𝑥 = 𝑦𝜑 )
Assertion naecoms-o ( ¬ ∀ 𝑦 𝑦 = 𝑥𝜑 )

Proof

Step Hyp Ref Expression
1 nalequcoms-o.1 ( ¬ ∀ 𝑥 𝑥 = 𝑦𝜑 )
2 aecom-o ( ∀ 𝑥 𝑥 = 𝑦 → ∀ 𝑦 𝑦 = 𝑥 )
3 2 1 nsyl4 ( ¬ 𝜑 → ∀ 𝑦 𝑦 = 𝑥 )
4 3 con1i ( ¬ ∀ 𝑦 𝑦 = 𝑥𝜑 )