Metamath Proof Explorer

Theorem orim2

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

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

Proof

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