Theorem pm4.44 791

Description: Theorem *4.44 of [WhiteheadRussell] p. 119. (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
pm4.44	|- ( ph <-> ( ph \/ ( ph /\ ps ) ) )

Proof of Theorem pm4.44

Step	Hyp	Ref	Expression
1		orc 724	. 2 |- ( ph -> ( ph \/ ( ph /\ ps ) ) )
2		id 19	. . 3 |- ( ph -> ph )
3		simpl 109	. . 3 |- ( ( ph /\ ps ) -> ph )
4	2, 3	jaoi 728	. 2 |- ( ( ph \/ ( ph /\ ps ) ) -> ph )
5	1, 4	impbii 126	1 |- ( ph <-> ( ph \/ ( ph /\ ps ) ) )

This proof depends on syntax axioms:   /\ wa 104   <-> wb 105   \/ 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)