Theorem pm3.1 501

Description: Theorem *3.1 of [WhiteheadRussell] p. 111. (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
pm3.1	|- ( ( ph /\ ps ) -> -. ( -. ph \/ -. ps ) )

Proof of Theorem pm3.1

Step	Hyp	Ref	Expression
1		anor 492	. 2 |- ( ( ph /\ ps ) <-> -. ( -. ph \/ -. ps ) )
2	1	biimpi 198	1 |- ( ( ph /\ ps ) -> -. ( -. ph \/ -. ps ) )

Syntax hints:   -. wn 3   -> wi 4   \/ wo 370   /\ wa 371

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 189  df-or 372  df-an 373

This theorem is referenced by:  pm3.14  505