Theorem orim2 789

Description: Axiom *1.6 (Sum) of [WhiteheadRussell] p. 97. (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
orim2	|- ( ( ps -> ch ) -> ( ( ph \/ ps ) -> ( ph \/ ch ) ) )

Proof of Theorem orim2

Step	Hyp	Ref	Expression
1		id 19	. 2 |- ( ( ps -> ch ) -> ( ps -> ch ) )
2	1	orim2d 788	1 |- ( ( ps -> ch ) -> ( ( ph \/ ps ) -> ( ph \/ ch ) ) )

Syntax hints:   -> wi 4   \/ wo 708

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-io 709

This theorem depends on definitions:  df-bi 117

This theorem is referenced by:  pm2.76  808  pm2.81  811