Theorem impi 143

Description: An importation inference.

Hypothesis

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

Assertion

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

Proof of Theorem impi

Step	Hyp	Ref	Expression
1		impi.1	. 2 |- (ph -> (ps -> ch))
2		impt 141	. 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:  bii 158  meredith 922

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

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