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Theorem pm2.49 661
Description: Theorem *2.49 of [WhiteheadRussell] p. 107. (Contributed by NM, 3-Jan-2005.)
Assertion
Ref Expression
pm2.49  |-  ( -.  ( ph  \/  ps )  ->  ( -.  ph  \/  -.  ps ) )

Proof of Theorem pm2.49
StepHypRef Expression
1 pm2.46 658 . 2  |-  ( -.  ( ph  \/  ps )  ->  -.  ps )
21olcd 653 1  |-  ( -.  ( ph  \/  ps )  ->  ( -.  ph  \/  -.  ps ) )
Colors of variables: wff set class
Syntax hints:   -. wn 3    -> wi 4    \/ wo 629
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-in1 544  ax-in2 545  ax-io 630
This theorem depends on definitions:  df-bi 110
This theorem is referenced by: (None)
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