Theorem biort 733

Description: A wff is disjoined with truth is true.

Assertion

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

Proof of Theorem biort

Step	Hyp	Ref	Expression
1		orc 269	. 2 |- (ph -> (ph \/ ps))
2		ax-1 4	. 2 |- (ph -> ((ph \/ ps) -> ph))
3	1, 2	impbid2 517	1 |- (ph -> (ph <-> (ph \/ ps)))

Syntax hints:   -> wi 3   <-> wb 146   \/ wo 222

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7

This theorem depends on definitions:  df-bi 147  df-or 224  df-an 225

Copyright terms: Public domain