Theorem expi 161

Description: An exportation inference. (The proof was shortened by O'Cat, 28-Nov-2008.)

Hypothesis

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

Assertion

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

Proof of Theorem expi

Step	Hyp	Ref	Expression
1		pm3.2im 137	. 2 |- (ph -> (ps -> -. (ph -> -. ps)))
2		expi.1	. 2 |- (-. (ph -> -. ps) -> ch)
3	1, 2	syl6 25	1 |- (ph -> (ps -> ch))

Syntax hints:  -. wn 2   -> wi 3

This theorem is referenced by:  bi3 167  pm3.2 305

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

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