Theorem truortru 1400

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

Assertion

Ref	Expression
truortru	|- ( ( T. \/ T. ) <-> T. )

Proof of Theorem truortru

Step	Hyp	Ref	Expression
1		oridm 752	1 |- ( ( T. \/ T. ) <-> T. )

Syntax hints:   <-> wb 104   \/ wo 703   T. wtru 1349

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 704

This theorem depends on definitions:  df-bi 116

This theorem is referenced by: (None)