Theorem pm5.14dc 911

Description: A decidable proposition is implied by or implies other propositions. Based on theorem *5.14 of [WhiteheadRussell] p. 123. (Contributed by Jim Kingdon, 30-Mar-2018.)

Assertion

Ref	Expression
pm5.14dc	|- (DECID ps -> ( ( ph -> ps ) \/ ( ps -> ch ) ) )

Proof of Theorem pm5.14dc

Step	Hyp	Ref	Expression
1		df-dc 835	. 2 |- (DECID ps <-> ( ps \/ -. ps ) )
2		ax-1 6	. . 3 |- ( ps -> ( ph -> ps ) )
3		ax-in2 615	. . 3 |- ( -. ps -> ( ps -> ch ) )
4	2, 3	orim12i 759	. 2 |- ( ( ps \/ -. ps ) -> ( ( ph -> ps ) \/ ( ps -> ch ) ) )
5	1, 4	sylbi 121	1 |- (DECID ps -> ( ( ph -> ps ) \/ ( ps -> ch ) ) )

Syntax hints:   -. wn 3   -> wi 4   \/ wo 708  DECID wdc 834

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in2 615  ax-io 709

This theorem depends on definitions:  df-bi 117  df-dc 835

This theorem is referenced by:  pm5.13dc  912