Theorem bnj593

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

	Ref	Expression
Hypotheses	bnj593.1	|- ( ph -> E. x ps )
	bnj593.2	|- ( ps -> ch )
Assertion	bnj593	|- ( ph -> E. x ch )

Proof

Step	Hyp	Ref	Expression
1		bnj593.1	|- ( ph -> E. x ps )
2		bnj593.2	|- ( ps -> ch )
3	2	eximi	|- ( E. x ps -> E. x ch )
4	1 3	syl	|- ( ph -> E. x ch )