Theorem pm2.45 689

Description: Theorem *2.45 of [WhiteheadRussell] p. 106. (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
pm2.45	|- ( -. ( ph \/ ps ) -> -. ph )

Proof of Theorem pm2.45

Step	Hyp	Ref	Expression
1		orc 665	. 2 |- ( ph -> ( ph \/ ps ) )
2	1	con3i 594	1 |- ( -. ( ph \/ ps ) -> -. ph )

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-in1 576  ax-in2 577  ax-io 662

This theorem depends on definitions:  df-bi 115

This theorem is referenced by:  pm2.47  691  ioran  701  dn1dc  901  eueq3dc  2766