Theorem 19.39

Description: Theorem 19.39 of Margaris p. 90. (Contributed by NM, 12-Mar-1993)

	Ref	Expression
Assertion	19.39	|- ( ( E. x ph -> E. x ps ) -> E. x ( ph -> ps ) )

Proof

Step	Hyp	Ref	Expression
1		19.2	|- ( A. x ph -> E. x ph )
2	1	imim1i	|- ( ( E. x ph -> E. x ps ) -> ( A. x ph -> E. x ps ) )
3		19.35	|- ( E. x ( ph -> ps ) <-> ( A. x ph -> E. x ps ) )
4	2 3	sylibr	|- ( ( E. x ph -> E. x ps ) -> E. x ( ph -> ps ) )