Theorem pm1.4 739

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 723	. 2 |- ( ph -> ( ps \/ ph ) )
2		orc 724	. 2 |- ( ps -> ( ps \/ ph ) )
3	1, 2	jaoi 728	1 |- ( ( ph \/ ps ) -> ( ps \/ ph ) )

Syntax hints:   -> wi 4   \/ wo 720

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 721

This theorem depends on definitions:  df-bi 117

This theorem is referenced by:  orcom  740  orcoms  742  pm2.3  787  pm2.36  816  pm2.37  817  pm2.8  822  dveeq2or  1869  prneimg  3894