Theorem expt 148

Description: Exportation theorem expressed with primitive connectives. (Contributed by NM, 5-Aug-1993.)

Assertion

Ref	Expression
expt	|- ((-. (ph -> -. ps) -> ch) -> (ph -> (ps -> ch)))

Proof of Theorem expt

Step	Hyp	Ref	Expression
1		pm3.2im 137	. . 3 |- (ph -> (ps -> -. (ph -> -. ps)))
2	1	imim1d 69	. 2 |- (ph -> ((-. (ph -> -. ps) -> ch) -> (ps -> ch)))
3	2	com12 27	1 |- ((-. (ph -> -. ps) -> ch) -> (ph -> (ps -> ch)))

Syntax hints:  -. wn 3   -> wi 4

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem is referenced by: (None)