Theorem nottru 1391

Description: A -. identity. (Contributed by Anthony Hart, 22-Oct-2010.)

Assertion

Ref	Expression
nottru	|- ( -. T. <-> F. )

Proof of Theorem nottru

Step	Hyp	Ref	Expression
1		df-fal 1337	. 2 |- ( F. <-> -. T. )
2	1	bicomi 131	1 |- ( -. T. <-> F. )

Syntax hints:   -. wn 3   <-> wb 104   T. wtru 1332   F. wfal 1336

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107

This theorem depends on definitions:  df-bi 116  df-fal 1337

This theorem is referenced by:  truxortru  1397