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Theorem truimfal 1345
Description: A identity. (Contributed by Anthony Hart, 22-Oct-2010.) (Proof shortened by Andrew Salmon, 13-May-2011.)
Assertion
Ref Expression
truimfal (( ⊤ → ⊥ ) ↔ ⊥ )

Proof of Theorem truimfal
StepHypRef Expression
1 tru 1321 . . 3
21a1bi 327 . 2 ( ⊥ ↔ ( ⊤ → ⊥ ))
32bicomi 193 1 (( ⊤ → ⊥ ) ↔ ⊥ )
Colors of variables: wff setvar class
Syntax hints:  wi 4  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
This theorem is referenced by: (None)
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