Theorem pm3.12 316

Description: Theorem *3.12 of [WhiteheadRussell] p. 111.

Assertion

Ref	Expression
pm3.12	|- ((-. ph \/ -. ps) \/ (ph /\ ps))

Proof of Theorem pm3.12

Step	Hyp	Ref	Expression
1		pm3.11 315	. 2 |- (-. (-. ph \/ -. ps) -> (ph /\ ps))
2	1	orri 231	1 |- ((-. ph \/ -. ps) \/ (ph /\ ps))

Syntax hints:  -. wn 2   \/ wo 222   /\ wa 223

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7

This theorem depends on definitions:  df-bi 147  df-or 224  df-an 225

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