Theorem pm1.4 728

Description: Axiom *1.4 of [WhiteheadRussell] p. 96. (Contributed by NM, 3-Jan-2005.) (Revised by NM, 15-Nov-2012.)

Assertion

Ref	Expression
pm1.4	|- ( ( ph \/ ps ) -> ( ps \/ ph ) )

Proof of Theorem pm1.4

Step	Hyp	Ref	Expression
1		olc 712	. 2 |- ( ph -> ( ps \/ ph ) )
2		orc 713	. 2 |- ( ps -> ( ps \/ ph ) )
3	1, 2	jaoi 717	1 |- ( ( ph \/ ps ) -> ( ps \/ ph ) )

Syntax hints:   -> wi 4   \/ wo 709

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-io 710

This theorem depends on definitions:  df-bi 117

This theorem is referenced by:  orcom  729  orcoms  731  pm2.3  776  pm2.36  805  pm2.37  806  pm2.8  811  dveeq2or  1830  prneimg  3805