Theorem bnj1397

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

	Ref	Expression
Hypotheses	bnj1397.1	|- ( ph -> E. x ps )
	bnj1397.2	|- ( ps -> A. x ps )
Assertion	bnj1397	|- ( ph -> ps )

Proof

Step	Hyp	Ref	Expression
1		bnj1397.1	|- ( ph -> E. x ps )
2		bnj1397.2	|- ( ps -> A. x ps )
3	2	19.9h	|- ( E. x ps <-> ps )
4	1 3	sylib	|- ( ph -> ps )