Theorem pm2.48 230

Description: Theorem *2.48 of [WhiteheadRussell] p. 107.

Assertion

Ref	Expression
pm2.48	|- (-. (ph \/ ps) -> (ph \/ -. ps))

Proof of Theorem pm2.48

Step	Hyp	Ref	Expression
1		pm2.46 229	. . 3 |- (-. (ph \/ ps) -> -. ps)
2	1	a1d 14	. 2 |- (-. (ph \/ ps) -> (-. ph -> -. ps))
3	2	orrd 203	1 |- (-. (ph \/ ps) -> (ph \/ -. ps))

Syntax hints:  -. wn 1   -> wi 2   \/ wo 195

This theorem is referenced by:  pm2.85 439

This theorem was proved from axioms:  ax-1 3  ax-2 4  ax-3 5  ax-mp 6

This theorem depends on definitions:  df-bi 128  df-or 197

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