MPE Home Metamath Proof Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  MPE Home  >  Th. List  >  falbifal Structured version   Visualization version   GIF version

Theorem falbifal 1560
Description: A identity. (Contributed by Anthony Hart, 22-Oct-2010.) (Proof shortened by Andrew Salmon, 13-May-2011.)
Assertion
Ref Expression
falbifal ((⊥ ↔ ⊥) ↔ ⊤)

Proof of Theorem falbifal
StepHypRef Expression
1 biid 262 . 2 (⊥ ↔ ⊥)
21bitru 1537 1 ((⊥ ↔ ⊥) ↔ ⊤)
Colors of variables: wff setvar class
Syntax hints:  wb 207  wtru 1529  wfal 1540
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 208  df-tru 1531
This theorem is referenced by:  falxorfal  1576
  Copyright terms: Public domain W3C validator