Theorem truanOLD 1261

Description: Obsolete proof of truan 1260 as of 21-Jul-2019. (Contributed by FL, 20-Mar-2011.) (Proof modification is discouraged.) (New usage is discouraged.)

Assertion

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

Proof of Theorem truanOLD

Step	Hyp	Ref	Expression
1		simpr 103	. 2 |- ( ( T. /\ ph ) -> ph )
2		a1tru 1259	. . 3 |- ( ph -> T. )
3	2	ancri 307	. 2 |- ( ph -> ( T. /\ ph ) )
4	1, 3	impbii 117	1 |- ( ( T. /\ ph ) <-> ph )

Syntax hints:   /\ wa 97   <-> wb 98   T. wtru 1244

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101

This theorem depends on definitions:  df-bi 110  df-tru 1246

This theorem is referenced by: (None)