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Metamath Proof Explorer

Theorem pm2.63

Description: Theorem *2.63 of WhiteheadRussell p. 107. (Contributed by NM, 3-Jan-2005)

Ref Expression
Assertion pm2.63 
|- ( ( ph \/ ps ) -> ( ( -. ph \/ ps ) -> ps ) )

Proof

Step Hyp Ref Expression
1 pm2.53 
 |-  ( ( ph \/ ps ) -> ( -. ph -> ps ) )
2 idd 
 |-  ( ( ph \/ ps ) -> ( ps -> ps ) )
3 1 2 jaod 
 |-  ( ( ph \/ ps ) -> ( ( -. ph \/ ps ) -> ps ) )