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Theorem biort 904
Description: A wff disjoined with truth is true. (Contributed by NM, 23-May-1999.)
Assertion
Ref Expression
biort  |-  ( ph  ->  ( ph  <->  ( ph  \/  ps ) ) )

Proof of Theorem biort
StepHypRef Expression
1 orc 386 . 2  |-  ( ph  ->  ( ph  \/  ps ) )
2 ax-1 6 . 2  |-  ( ph  ->  ( ( ph  \/  ps )  ->  ph )
)
31, 2impbid2 207 1  |-  ( ph  ->  ( ph  <->  ( ph  \/  ps ) ) )
Colors of variables: wff setvar class
Syntax hints:    -> wi 4    <-> wb 187    \/ wo 369
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8
This theorem depends on definitions:  df-bi 188  df-or 371
This theorem is referenced by:  pm5.55  905
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