Theorem pm2.48 389

Description: Theorem *2.48 of [WhiteheadRussell] p. 107. (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
pm2.48	|- (-. (ph \/ ps) -> (ph \/ -. ps))

Proof of Theorem pm2.48

Step	Hyp	Ref	Expression
1		pm2.46 387	. 2 |- (-. (ph \/ ps) -> -. ps)
2	1	olcd 382	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)