Theorem pm2.37 889

Description: Theorem *2.37 of [WhiteheadRussell] p. 105. (Contributed by NM, 6-Mar-2008.)

Assertion

Ref	Expression
pm2.37	|- ( ( ps -> ch ) -> ( ( ps \/ ph ) -> ( ph \/ ch ) ) )

Proof of Theorem pm2.37

Step	Hyp	Ref	Expression
1		pm2.38 887	. 2 |- ( ( ps -> ch ) -> ( ( ps \/ ph ) -> ( ch \/ ph ) ) )
2		pm1.4 401	. 2 |- ( ( ch \/ ph ) -> ( ph \/ ch ) )
3	1, 2	syl6 35	1 |- ( ( ps -> ch ) -> ( ( ps \/ ph ) -> ( ph \/ ch ) ) )

Syntax hints:   -> 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  df-an 386

This theorem is referenced by: (None)