Theorem pm5.14 930

Description: Theorem *5.14 of [WhiteheadRussell] p. 123. (Contributed by NM, 3-Jan-2005.)

Assertion

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

Proof of Theorem pm5.14

Step	Hyp	Ref	Expression
1		ax-1 6	. . . 4 |- ( ps -> ( ph -> ps ) )
2	1	con3i 150	. . 3 |- ( -. ( ph -> ps ) -> -. ps )
3	2	pm2.21d 118	. 2 |- ( -. ( ph -> ps ) -> ( ps -> ch ) )
4	3	orri 391	1 |- ( ( ph -> ps ) \/ ( ps -> ch ) )

Syntax hints:   -. wn 3   -> wi 4   \/ 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:  pm5.13  931