Theorem bnj132

Description: First-order logic and set theory. (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (Proof shortened by Andrew Salmon, 26-Jun-2011) (New usage is discouraged.)

	Ref	Expression
Hypothesis	bnj132.1	|- ( ph <-> E. x ( ps -> ch ) )
Assertion	bnj132	|- ( ph <-> ( ps -> E. x ch ) )

Proof

Step	Hyp	Ref	Expression
1		bnj132.1	|- ( ph <-> E. x ( ps -> ch ) )
2		19.37v	|- ( E. x ( ps -> ch ) <-> ( ps -> E. x ch ) )
3	1 2	bitri	|- ( ph <-> ( ps -> E. x ch ) )