Theorem truorfal 1578

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

Assertion

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

Proof of Theorem truorfal

Step	Hyp	Ref	Expression
1		tru 1544	. . 3 ⊢ ⊤
2	1	orci 865	. 2 ⊢ (⊤ ∨ ⊥)
3	2	bitru 1549	1 ⊢ ((⊤ ∨ ⊥) ↔ ⊤)

Syntax hints:   ↔ wb 206   ∨ wo 847  ⊤wtru 1541  ⊥wfal 1552

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem depends on definitions:  df-bi 207  df-or 848  df-tru 1543

This theorem is referenced by:  trunorfal  1590