Theorem dftru2 1372

Description: An alternate definition of "true". (Contributed by Anthony Hart, 13-Oct-2010.) (Revised by BJ, 12-Jul-2019.) (New usage is discouraged.)

Assertion

Ref	Expression
dftru2	|- ( T. <-> ( ph -> ph ) )

Proof of Theorem dftru2

Step	Hyp	Ref	Expression
1		tru 1368	. 2 |- T.
2		id 19	. 2 |- ( ph -> ph )
3	1, 2	2th 174	1 |- ( T. <-> ( ph -> ph ) )

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)