Theorem truorfal 1337

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

Assertion

Ref	Expression
truorfal	⊢ ((⊤ ∨ ⊥) ↔ ⊤)

Proof of Theorem truorfal

Step	Hyp	Ref	Expression
1		tru 1288	. . 3 ⊢ ⊤
2	1	orci 682	. 2 ⊢ (⊤ ∨ ⊥)
3	2	bitru 1296	1 ⊢ ((⊤ ∨ ⊥) ↔ ⊤)

Syntax hints:   ↔ wb 103   ∨ wo 661  ⊤wtru 1285  ⊥wfal 1289

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-io 662

This theorem depends on definitions:  df-bi 115  df-tru 1287

This theorem is referenced by:  truxorfal  1351