Theorem i19.24 1530

Description: Theorem 19.24 of [Margaris] p. 90, with an additional hypothesis. The hypothesis is the converse of 19.35-1 1515, and is a theorem of classical logic, but in intuitionistic logic it will only be provable for some propositions. (Contributed by Jim Kingdon, 22-Jul-2018.)

Hypothesis

Ref	Expression
i19.24.1	|- ( ( A. x ph -> E. x ps ) -> E. x ( ph -> ps ) )

Assertion

Ref	Expression
i19.24	|- ( ( A. x ph -> A. x ps ) -> E. x ( ph -> ps ) )

Proof of Theorem i19.24

Step	Hyp	Ref	Expression
1		19.2 1529	. . 3 |- ( A. x ps -> E. x ps )
2	1	imim2i 12	. 2 |- ( ( A. x ph -> A. x ps ) -> ( A. x ph -> E. x ps ) )
3		i19.24.1	. 2 |- ( ( A. x ph -> E. x ps ) -> E. x ( ph -> ps ) )
4	2, 3	syl 14	1 |- ( ( A. x ph -> A. x ps ) -> E. x ( ph -> ps ) )

Syntax hints:   -> wi 4   A.wal 1241   E.wex 1381

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-gen 1338  ax-ie1 1382  ax-ie2 1383  ax-4 1400

This theorem depends on definitions:  df-bi 110

This theorem is referenced by: (None)