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Metamath Proof Explorer

Theorem pm2.46

Description: Theorem *2.46 of WhiteheadRussell p. 106. (Contributed by NM, 3-Jan-2005)

Ref Expression
Assertion pm2.46 
|- ( -. ( ph \/ ps ) -> -. ps )

Proof

Step Hyp Ref Expression
1 olc 
 |-  ( ps -> ( ph \/ ps ) )
2 1 con3i 
 |-  ( -. ( ph \/ ps ) -> -. ps )