Theorem pm5.11 854

Description: Theorem *5.11 of [WhiteheadRussell] p. 123. (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
pm5.11	|- ((ph -> ps) \/ (-. ph -> ps))

Proof of Theorem pm5.11

Step	Hyp	Ref	Expression
1		pm2.5 144	. 2 |- (-. (ph -> ps) -> (-. ph -> ps))
2	1	orri 365	1 |- ((ph -> ps) \/ (-. ph -> ps))

This proof depends on syntax axioms:  -. wn 3   -> wi 4   \/ wo 357

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This proof depends on definitions:  df-bi 177  df-or 359

This theorem is used by: (None)