Metamath Proof Explorer

Theorem pm2.36

Description: Theorem *2.36 of WhiteheadRussell p. 105. (Contributed by NM, 6-Mar-2008)

Ref Expression
Assertion pm2.36 
|- ( ( ps -> ch ) -> ( ( ph \/ ps ) -> ( ch \/ ph ) ) )

Proof

Step Hyp Ref Expression
1 pm1.4 
 |-  ( ( ph \/ ps ) -> ( ps \/ ph ) )
2 pm2.38 
 |-  ( ( ps -> ch ) -> ( ( ps \/ ph ) -> ( ch \/ ph ) ) )
3 1 2 syl5 
 |-  ( ( ps -> ch ) -> ( ( ph \/ ps ) -> ( ch \/ ph ) ) )