Theorem pm2.26 883

Description: Theorem *2.26 of [WhiteheadRussell] p. 104. (Contributed by NM, 3-Jan-2005.) (Proof shortened by Wolf Lammen, 23-Nov-2012.)

Assertion

Ref	Expression
pm2.26

Proof of Theorem pm2.26

Step	Hyp	Ref	Expression
1		pm2.27 39	. 2
2	1	imori 413	1

Syntax hints:  -.wn 3  ->wi 4  \/wo 368

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  df-or 370