Theorem pm1.2 535

Description: Axiom *1.2 of [WhiteheadRussell] p. 96, which they call "Taut". (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
pm1.2	|- ( ( ph \/ ph ) -> ph )

Proof of Theorem pm1.2

Step	Hyp	Ref	Expression
1		id 22	. 2 |- ( ph -> ph )
2	1, 1	jaoi 394	1 |- ( ( ph \/ ph ) -> ph )

Syntax hints:   -> wi 4   \/ wo 383

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem depends on definitions:  df-bi 197  df-or 385

This theorem is referenced by:  oridm  536  rb-ax4  1680  sotrieq  5062  swoer  7772  bj-peirce  32543  paddidm  35127