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	⊢ ( ( ⊥ ↔ ⊤ ) ↔ ⊥ )