Theorem truimtru 1420

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

Assertion

Ref	Expression
truimtru	|- ( ( T. -> T. ) <-> T. )

Proof of Theorem truimtru

Step	Hyp	Ref	Expression
1		id 19	. 2 |- ( T. -> T. )
2	1	bitru 1376	1 |- ( ( T. -> T. ) <-> T. )

Syntax hints:   -> wi 4   <-> wb 105   T. wtru 1365

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108

This theorem depends on definitions:  df-bi 117  df-tru 1367

This theorem is referenced by: (None)