Theorem pm1.2 728

Description: Axiom *1.2 (Taut) of [WhiteheadRussell] p. 96. (Contributed by NM, 3-Jan-2005.) (Revised by NM, 10-Mar-2013.)

Assertion

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

Proof of Theorem pm1.2

Step	Hyp	Ref	Expression
1		id 19	. 2 |- ( ph -> ph )
2	1, 1	jaoi 688	1 |- ( ( ph \/ ph ) -> ph )

Syntax hints:   -> wi 4   \/ wo 680

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 681

This theorem depends on definitions:  df-bi 116

This theorem is referenced by:  oridm  729  sbequi  1791  swoer  6409