Metamath Proof Explorer

Theorem falbitru

Description: A <-> identity. (Contributed by Anthony Hart, 22-Oct-2010) (Proof shortened by Andrew Salmon, 13-May-2011) (Proof shortened by Wolf Lammen, 10-Jul-2020)

Ref Expression
Assertion falbitru ⊢ ⊥ ↔ ⊤ ↔ ⊥

Proof

Step Hyp Ref Expression
1 tbtru ⊢ ⊥ ↔ ⊥ ↔ ⊤
2 1 bicomi ⊢ ⊥ ↔ ⊤ ↔ ⊥