Theorem pm2.64 764

Description: Theorem *2.64 of [WhiteheadRussell] p. 107. (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
pm2.64	|- ((ph \/ ps) -> ((ph \/ -. ps) -> ph))

Proof of Theorem pm2.64

Step	Hyp	Ref	Expression
1		ax-1 6	. . 3 |- (ph -> ((ph \/ ps) -> ph))
2		orel2 372	. . 3 |- (-. ps -> ((ph \/ ps) -> ph))
3	1, 2	jaoi 368	. 2 |- ((ph \/ -. ps) -> ((ph \/ ps) -> ph))
4	3	com12 27	1 |- ((ph \/ ps) -> ((ph \/ -. ps) -> ph))

Syntax hints:  -. wn 3   -> wi 4   \/ wo 357

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

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

This theorem is referenced by: (None)