Theorem expi 144

Description: An exportation inference.

Hypothesis

Ref	Expression
expi.1	|- (-. (ph -> -. ps) -> ch)

Assertion

Ref	Expression
expi	|- (ph -> (ps -> ch))

Proof of Theorem expi

Step	Hyp	Ref	Expression
1		expi.1	. 2 |- (-. (ph -> -. ps) -> ch)
2		expt 142	. 2 |- ((-. (ph -> -. ps) -> ch) -> (ph -> (ps -> ch)))
3	1, 2	ax-mp 7	1 |- (ph -> (ps -> ch))

Syntax hints:  -. wn 2   -> wi 3

This theorem is referenced by:  bi3 150  pm3.2 283

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

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