Theorem imimorbdc 828

Description: Simplify an implication between implications, for a decidable proposition. (Contributed by Jim Kingdon, 18-Mar-2018.)

Assertion

Ref	Expression
imimorbdc	|- (DECID ps -> ( ( ( ps -> ch ) -> ( ph -> ch ) ) <-> ( ph -> ( ps \/ ch ) ) ) )

Proof of Theorem imimorbdc

Step	Hyp	Ref	Expression
1		dfor2dc 827	. . 3 |- (DECID ps -> ( ( ps \/ ch ) <-> ( ( ps -> ch ) -> ch ) ) )
2	1	imbi2d 228	. 2 |- (DECID ps -> ( ( ph -> ( ps \/ ch ) ) <-> ( ph -> ( ( ps -> ch ) -> ch ) ) ) )
3		bi2.04 246	. 2 |- ( ( ( ps -> ch ) -> ( ph -> ch ) ) <-> ( ph -> ( ( ps -> ch ) -> ch ) ) )
4	2, 3	syl6rbbr 197	1 |- (DECID ps -> ( ( ( ps -> ch ) -> ( ph -> ch ) ) <-> ( ph -> ( ps \/ ch ) ) ) )

Syntax hints:   -> wi 4   <-> wb 103   \/ wo 661  DECID wdc 775

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-in1 576  ax-in2 577  ax-io 662

This theorem depends on definitions:  df-bi 115  df-dc 776

This theorem is referenced by: (None)