Metamath Proof Explorer

Theorem pm2.76

Description: Theorem *2.76 of WhiteheadRussell p. 108. (Contributed by NM, 3-Jan-2005)

Ref Expression
Assertion pm2.76 
|- ( ( ph \/ ( ps -> ch ) ) -> ( ( ph \/ ps ) -> ( ph \/ ch ) ) )

Proof

Step Hyp Ref Expression
1 orimdi 
 |-  ( ( ph \/ ( ps -> ch ) ) <-> ( ( ph \/ ps ) -> ( ph \/ ch ) ) )
2 1 biimpi 
 |-  ( ( ph \/ ( ps -> ch ) ) -> ( ( ph \/ ps ) -> ( ph \/ ch ) ) )