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Theorem falbitru 1352
Description: A identity. (Contributed by Anthony Hart, 22-Oct-2010.) (Proof shortened by Andrew Salmon, 13-May-2011.)
Assertion
Ref Expression
falbitru (( ⊥ ↔ ⊤ ) ↔ ⊥ )

Proof of Theorem falbitru
StepHypRef Expression
1 bicom 191 . 2 (( ⊥ ↔ ⊤ ) ↔ ( ⊤ ↔ ⊥ ))
2 trubifal 1351 . 2 (( ⊤ ↔ ⊥ ) ↔ ⊥ )
31, 2bitri 240 1 (( ⊥ ↔ ⊤ ) ↔ ⊥ )
Colors of variables: wff setvar class
Syntax hints:  wb 176  wtru 1316  wfal 1317
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 177  df-tru 1319  df-fal 1320
This theorem is referenced by:  falxortru  1360
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