Theorem pm2.48 753

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		pm2.46 751	. 2 |- ( -. ( ph \/ ps ) -> -. ps )
2	1	olcd 746	1 |- ( -. ( ph \/ ps ) -> ( ph \/ -. ps ) )

This proof depends on syntax axioms:   -. wn 3   -> wi 4   \/ wo 720

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 623  ax-in2 624  ax-io 721

This proof depends on definitions:  df-bi 117

This theorem is used by: (None)