Theorem pm2.48 692

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		pm2.46 690	. 2 |- ( -. ( ph \/ ps ) -> -. ps )
2	1	olcd 685	1 |- ( -. ( ph \/ ps ) -> ( ph \/ -. ps ) )

Syntax hints:   -. wn 3   -> wi 4   \/ wo 661

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-in1 576  ax-in2 577  ax-io 662

This theorem depends on definitions:  df-bi 115

This theorem is referenced by: (None)