Theorem nottru 1348

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 1320	. 2 |- ( F. <-> -. T. )
2	1	bicomi 193	1 |- (-. T. <-> F. )

Syntax hints:  -. wn 3   <-> wb 176   T. wtru 1316   F. 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-fal 1320

This theorem is referenced by:  trubifal  1351  trunantru  1354  truxortru  1358  falxorfal  1361