Theorem bj-alalbial

Description: Adding a second quantifier is a tranparent operation, ( A. A. case). (Contributed by BJ, 20-Oct-2019)

	Ref	Expression
Assertion	bj-alalbial	⊢ ( ∀ 𝑥 ∀ 𝑥 𝜑 ↔ ∀ 𝑥 𝜑 )

Proof

Step	Hyp	Ref	Expression
1		nfa1	⊢ Ⅎ 𝑥 ∀ 𝑥 𝜑
2	1	19.3	⊢ ( ∀ 𝑥 ∀ 𝑥 𝜑 ↔ ∀ 𝑥 𝜑 )