Metamath Proof Explorer

Theorem falnanfal

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

Ref Expression
Assertion falnanfal 
|- ( ( F. -/\ F. ) <-> T. )

Proof

Step Hyp Ref Expression
1 nannot 
 |-  ( -. F. <-> ( F. -/\ F. ) )
2 notfal 
 |-  ( -. F. <-> T. )
3 1 2 bitr3i 
 |-  ( ( F. -/\ F. ) <-> T. )