Theorem truortru 1340

Description: A ∨ identity. (Contributed by Anthony Hart, 22-Oct-2010.) (Proof shortened by Andrew Salmon, 13-May-2011.)

Assertion

Ref	Expression
truortru	⊢ (( ⊤ ∨ ⊤ ) ↔ ⊤ )

Proof of Theorem truortru

Step	Hyp	Ref	Expression
1		oridm 500	1 ⊢ (( ⊤ ∨ ⊤ ) ↔ ⊤ )

This proof depends on syntax axioms:   ↔ wb 176   ∨ wo 357   ⊤ wtru 1316

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This proof depends on definitions:  df-bi 177  df-or 359

This theorem is used by: (None)