Theorem pm2.1 656

Description: Theorem *2.1 of [WhiteheadRussell] p. 101.

Assertion

Ref	Expression
pm2.1	|- (-. ph \/ ph)

Proof of Theorem pm2.1

Step	Hyp	Ref	Expression
1		nega 84	. 2 |- (-. -. ph -> ph)
2	1	orri 231	1 |- (-. ph \/ ph)

Syntax hints:  -. wn 2   \/ wo 222

This theorem is referenced by:  pwundif 2828  lelttrit 5622  hiidge0t 8964

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7

This theorem depends on definitions:  df-bi 147  df-or 224

Copyright terms: Public domain