Theorem pm3.2im 122

Description: Theorem *3.2 of [WhiteheadRussell] p. 111, expressed with primitive connectives. (The proof was shortened by Josh Purinton, 29-Dec-2000.)

Assertion

Ref	Expression
pm3.2im	|- (ph -> (ps -> -. (ph -> -. ps)))

Proof of Theorem pm3.2im

Step	Hyp	Ref	Expression
1		pm2.27 62	. 2 |- (ph -> ((ph -> -. ps) -> -. ps))
2	1	con2d 91	1 |- (ph -> (ps -> -. (ph -> -. ps)))

Syntax hints:  -. wn 2   -> wi 3

This theorem is referenced by:  pm2.65 134  jc 138  expt 142

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

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