Theorem pm2.53 254

Description: Theorem *2.53 of [WhiteheadRussell] p. 107.

Assertion

Ref	Expression
pm2.53	|- ((ph \/ ps) -> (-. ph -> ps))

Proof of Theorem pm2.53

Step	Hyp	Ref	Expression
1		orel1 251	. 2 |- (-. ph -> ((ph \/ ps) -> ps))
2	1	com12 11	1 |- ((ph \/ ps) -> (-. ph -> ps))

Syntax hints:  -. wn 2   -> wi 3   \/ wo 222

This theorem is referenced by:  pm5.63 346  pm2.63 428

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

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