Theorem pm4.8 365

Description: Theorem *4.8 of [WhiteheadRussell] p. 122. (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
pm4.8

Proof of Theorem pm4.8

Step	Hyp	Ref	Expression
1		pm2.01 168	. 2
2		ax-1 6	. 2
3	1, 2	impbii 188	1

Syntax hints:  -.wn 3  ->wi 4  <->wb 184

This theorem is referenced by:  bj-ifimimb  37715

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 185