Theorem nfa2

Description: Lemma 24 of Monk2 p. 114. (Contributed by Mario Carneiro, 24-Sep-2016) Remove dependency on ax-12 . (Revised by Wolf Lammen, 18-Oct-2021)

	Ref	Expression
Assertion	nfa2	|- F/ x A. y A. x ph

Proof

Step	Hyp	Ref	Expression
1		alcom	|- ( A. y A. x ph <-> A. x A. y ph )
2		nfa1	|- F/ x A. x A. y ph
3	1 2	nfxfr	|- F/ x A. y A. x ph