Theorem biort 938

Description: A wff disjoined with truth is true. (Contributed by NM, 23-May-1999.)

Assertion

Ref	Expression
biort	|- ( ph -> ( ph <-> ( ph \/ ps ) ) )

Proof of Theorem biort

Step	Hyp	Ref	Expression
1		orc 400	. 2 |- ( ph -> ( ph \/ ps ) )
2		ax-1 6	. 2 |- ( ph -> ( ( ph \/ ps ) -> ph ) )
3	1, 2	impbid2 216	1 |- ( ph -> ( ph <-> ( ph \/ ps ) ) )

Syntax hints:   -> wi 4   <-> wb 196   \/ wo 383

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem depends on definitions:  df-bi 197  df-or 385

This theorem is referenced by:  pm5.55  939