Users' Mathboxes Mathbox for Frédéric Liné < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  MPE Home  >  Th. List  >   Mathboxes  >  tnf Unicode version

Theorem tnf 24952
Description: True is not false. (Contributed by FL, 20-Mar-2011.)
Assertion
Ref Expression
tnf  |-  (  T.  <->  -. 
F.  )

Proof of Theorem tnf
StepHypRef Expression
1 df-fal 1311 . 2  |-  (  F.  <->  -.  T.  )
21con2bii 322 1  |-  (  T.  <->  -. 
F.  )
Colors of variables: wff set class
Syntax hints:   -. wn 3    <-> wb 176    T. wtru 1307    F. wfal 1308
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 177  df-fal 1311
  Copyright terms: Public domain W3C validator