Theorem expt 123

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 107	. . 3 |- (ph -> (ps -> -. (ph -> -. ps)))
2	1	syl4d 28	. 2 |- (ph -> ((-. (ph -> -. ps) -> ch) -> (ps -> ch)))
3	2	com12 13	1 |- ((-. (ph -> -. ps) -> ch) -> (ph -> (ps -> ch)))

Syntax hints:  -. wn 1   -> wi 2

This theorem is referenced by:  expi 125  impexp 276

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

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