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Theorem falxortru 1369
Description: A  \/_ identity. (Contributed by David A. Wheeler, 9-May-2015.)
Assertion
Ref Expression
falxortru  |-  ( (  F.  \/_  T.  )  <->  T.  )

Proof of Theorem falxortru
StepHypRef Expression
1 df-xor 1314 . 2  |-  ( (  F.  \/_  T.  )  <->  -.  (  F.  <->  T.  )
)
2 falbitru 1361 . . 3  |-  ( (  F.  <->  T.  )  <->  F.  )
32notbii 288 . 2  |-  ( -.  (  F.  <->  T.  )  <->  -. 
F.  )
4 notfal 1358 . 2  |-  ( -. 
F. 
<->  T.  )
51, 3, 43bitri 263 1  |-  ( (  F.  \/_  T.  )  <->  T.  )
Colors of variables: wff set class
Syntax hints:   -. wn 3    <-> wb 177    \/_ wxo 1313    T. wtru 1325    F. wfal 1326
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8
This theorem depends on definitions:  df-bi 178  df-xor 1314  df-tru 1328  df-fal 1329
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