Theorem biort 550

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 225	. . 3 |- (ph -> (ph \/ ps))
2	1	a1d 14	. 2 |- (ph -> (ph -> (ph \/ ps)))
3		ax-1 3	. 2 |- (ph -> ((ph \/ ps) -> ph))
4	2, 3	impbid 397	1 |- (ph -> (ph <-> (ph \/ ps)))

Syntax hints:   -> wi 2   <-> wb 127   \/ wo 195

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

This theorem depends on definitions:  df-bi 128  df-or 197  df-an 198

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