Theorem pm1.4 678

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 664	. 2 |- ( ph -> ( ps \/ ph ) )
2		orc 665	. 2 |- ( ps -> ( ps \/ ph ) )
3	1, 2	jaoi 668	1 |- ( ( ph \/ ps ) -> ( ps \/ ph ) )

Syntax hints:   -> wi 4   \/ wo 661

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-io 662

This theorem depends on definitions:  df-bi 115

This theorem is referenced by:  orcom  679  orcoms  681  pm2.3  724  pm2.36  750  pm2.37  751  pm2.8  756  dveeq2or  1737  prneimg  3566