Theorem nottru 1304

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 1249	. 2 |- ( F. <-> -. T. )
2	1	bicomi 123	1 |- ( -. T. <-> F. )

Syntax hints:   -. wn 3   <-> wb 98   T. wtru 1244   F. wfal 1248

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101

This theorem depends on definitions:  df-bi 110  df-fal 1249

This theorem is referenced by:  truxortru  1310