Theorem pm1.4 247

Description: Axiom *1.4 of [WhiteheadRussell] p. 96.

Assertion

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

Proof of Theorem pm1.4

Step	Hyp	Ref	Expression
1		orcom 246	. 2 |- ((ph \/ ps) <-> (ps \/ ph))
2	1	biimp 151	1 |- ((ph \/ ps) -> (ps \/ ph))

Syntax hints:   -> wi 3   \/ wo 222

This theorem is referenced by:  pm2.3 339  pm2.36 572  pm2.37 573

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

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