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Metamath Proof Explorer

Theorem nfaba1OLD

Description: Obsolete version of nfaba1 as of 14-May-2025. (Contributed by Mario Carneiro, 14-Oct-2016) (Revised by GG, 20-Jan-2024) (Proof modification is discouraged.) (New usage is discouraged.)

		Ref	Expression
	Assertion	nfaba1OLD	\|- F/_ x { y \| A. x ph }

Proof

Step	Hyp	Ref	Expression
1		nfa1	\|- F/ x A. x ph
2	1	nfab	\|- F/_ x { y \| A. x ph }