Theorem pm2.37OLD 99

Description: This is NOT theorem *2.37 of [WhiteheadRussell] p. 105.

Assertion

Ref	Expression
pm2.37OLD	|- ((ps -> ch) -> ((-. ps -> ph) -> (-. ph -> ch)))

Proof of Theorem pm2.37OLD

Step	Hyp	Ref	Expression
1		con1 92	. . 3 |- ((-. ps -> ph) -> (-. ph -> ps))
2	1	imim1d 28	. 2 |- ((-. ps -> ph) -> ((ps -> ch) -> (-. ph -> ch)))
3	2	com12 11	1 |- ((ps -> ch) -> ((-. ps -> ph) -> (-. ph -> ch)))

Syntax hints:  -. wn 2   -> wi 3

This theorem is referenced by:  pm2.61-ocatOLD 125

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

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