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Theorem pm4.65r 821
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
StepHypRef Expression
1 annimim 820 1  |-  ( ( -.  ph  /\  -.  ps )  ->  -.  ( -.  ph 
->  ps ) )
Colors of variables: wff set class
Syntax hints:   -. wn 3    -> wi 4    /\ wa 102
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-in1 579  ax-in2 580
This theorem is referenced by: (None)
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