Theorem pm2.4 790

Description: Theorem *2.4 of [WhiteheadRussell] p. 106. (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
pm2.4	|- ( ( ph \/ ( ph \/ ps ) ) -> ( ph \/ ps ) )

Proof of Theorem pm2.4

Step	Hyp	Ref	Expression
1		orc 724	. 2 |- ( ph -> ( ph \/ ps ) )
2		id 19	. 2 |- ( ( ph \/ ps ) -> ( ph \/ ps ) )
3	1, 2	jaoi 728	1 |- ( ( ph \/ ( ph \/ ps ) ) -> ( ph \/ ps ) )

This proof depends on syntax axioms:   -> wi 4   \/ wo 720

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-io 721

This proof depends on definitions:  df-bi 117

This theorem is used by: (None)