Theorem bnj1436

Description: First-order logic and set theory. (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)

	Ref	Expression
Hypothesis	bnj1436.1	|- A = { x | ph }
Assertion	bnj1436	|- ( x e. A -> ph )

Proof

Step	Hyp	Ref	Expression
1		bnj1436.1	|- A = { x | ph }
2	1	abeq2i	|- ( x e. A <-> ph )
3	2	biimpi	|- ( x e. A -> ph )