Theorem expt 142

Description: Exportation theorem expressed with primitive connectives.

Assertion

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

Proof of Theorem expt

Step	Hyp	Ref	Expression
1		pm3.2im 122	. . 3 |- (ph -> (ps -> -. (ph -> -. ps)))
2	1	imim1d 28	. 2 |- (ph -> ((-. (ph -> -. ps) -> ch) -> (ps -> ch)))
3	2	com12 11	1 |- ((-. (ph -> -. ps) -> ch) -> (ph -> (ps -> ch)))

Syntax hints:  -. wn 2   -> wi 3

This theorem is referenced by:  expi 144  impexp 347

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7

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