Theorem pm2.75 822

Description: Theorem *2.75 of [WhiteheadRussell] p. 108. (Contributed by NM, 3-Jan-2005.) (Proof shortened by Wolf Lammen, 4-Jan-2013.)

Assertion

Ref	Expression
pm2.75	|- ((ph \/ ps) -> ((ph \/ (ps -> ch)) -> (ph \/ ch)))

Proof of Theorem pm2.75

Step	Hyp	Ref	Expression
1		pm2.76 821	. 2 |- ((ph \/ (ps -> ch)) -> ((ph \/ ps) -> (ph \/ ch)))
2	1	com12 27	1 |- ((ph \/ ps) -> ((ph \/ (ps -> ch)) -> (ph \/ ch)))

This proof depends on syntax axioms:   -> 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)