Theorem rabid2

Description: An "identity" law for restricted class abstraction. (Contributed by NM, 9-Oct-2003) (Proof shortened by Andrew Salmon, 30-May-2011) (Proof shortened by Wolf Lammen, 24-Nov-2024)

	Ref	Expression
Assertion	rabid2	|- ( A = { x e. A | ph } <-> A. x e. A ph )

Proof

Step	Hyp	Ref	Expression
1		nfcv	|- F/_ x A
2	1	rabid2f	|- ( A = { x e. A | ph } <-> A. x e. A ph )