Metamath Proof Explorer

Theorem notfal

Description: A -. identity. (Contributed by Anthony Hart, 22-Oct-2010) (Proof shortened by Andrew Salmon, 13-May-2011)

Ref Expression
Assertion notfal 
|- ( -. F. <-> T. )

Proof

Step Hyp Ref Expression
1 fal 
 |-  -. F.
2 1 bitru 
 |-  ( -. F. <-> T. )