Theorem falimfal 1402

Description: A → identity. (Contributed by Anthony Hart, 22-Oct-2010.)

Assertion

Ref	Expression
falimfal	⊢ ((⊥ → ⊥) ↔ ⊤)

Proof of Theorem falimfal

Step	Hyp	Ref	Expression
1		id 19	. 2 ⊢ (⊥ → ⊥)
2	1	bitru 1355	1 ⊢ ((⊥ → ⊥) ↔ ⊤)

Syntax hints:   → wi 4   ↔ wb 104  ⊤wtru 1344  ⊥wfal 1348

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107

This theorem depends on definitions:  df-bi 116  df-tru 1346

This theorem is referenced by: (None)