Theorem pm2.37 718

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		pm2.38 716	. 2 |- ( ( ps -> ch ) -> ( ( ps \/ ph ) -> ( ch \/ ph ) ) )
2		pm1.4 646	. 2 |- ( ( ch \/ ph ) -> ( ph \/ ch ) )
3	1, 2	syl6 29	1 |- ( ( ps -> ch ) -> ( ( ps \/ ph ) -> ( ph \/ ch ) ) )

Syntax hints:   -> wi 4   \/ wo 629

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-io 630

This theorem depends on definitions:  df-bi 110

This theorem is referenced by: (None)