Theorem pm4.65r 783

Description: One direction of Theorem *4.65 of [WhiteheadRussell] p. 120. The converse holds in classical logic. (Contributed by Jim Kingdon, 28-Jul-2018.)

Assertion

Ref	Expression
pm4.65r	|- ( ( -. ph /\ -. ps ) -> -. ( -. ph -> ps ) )

Proof of Theorem pm4.65r

Step	Hyp	Ref	Expression
1		annimim 782	1 |- ( ( -. ph /\ -. ps ) -> -. ( -. ph -> ps ) )

Syntax hints:   -. wn 3   -> wi 4   /\ wa 97

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-in1 544  ax-in2 545

This theorem is referenced by: (None)