Theorem truorfal 1297

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

Assertion

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

Proof of Theorem truorfal

Step	Hyp	Ref	Expression
1		tru 1247	. . 3 ⊢ ⊤
2	1	orci 650	. 2 ⊢ (⊤ ∨ ⊥)
3	2	bitru 1255	1 ⊢ ((⊤ ∨ ⊥) ↔ ⊤)

Syntax hints:   ↔ wb 98   ∨ wo 629  ⊤wtru 1244  ⊥wfal 1248

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-io 630

This theorem depends on definitions:  df-bi 110  df-tru 1246

This theorem is referenced by:  truxorfal  1311