Theorem pm3.2im 157

Description: Theorem *3.2 of [WhiteheadRussell] p. 111, expressed with primitive connectives (see pm3.2 463). (Contributed by NM, 29-Dec-1992.) (Proof 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 42	. 2 |- ( ph -> ( ( ph -> -. ps ) -> -. ps ) )
2	1	con2d 129	1 |- ( ph -> ( ps -> -. ( ph -> -. ps ) ) )

Syntax hints:   -. wn 3   -> wi 4

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem is referenced by:  jc  159  expi  161  expt  168