Theorem retbwax3 1648

Description: tbw-ax3 1627 rederived from merco1 1638. (Contributed by Anthony Hart, 17-Sep-2011.) (Proof modification is discouraged.) (New usage is discouraged.)

Assertion

Ref	Expression
retbwax3	|- ( ( ( ph -> ps ) -> ph ) -> ph )

Proof of Theorem retbwax3

Step	Hyp	Ref	Expression
1		retbwax2 1641	. 2 |- ( ph -> ( ph -> ph ) )
2		merco1lem7 1647	. 2 |- ( ( ph -> ( ph -> ph ) ) -> ( ( ( ph -> ps ) -> ph ) -> ph ) )
3	1, 2	ax-mp 5	1 |- ( ( ( ph -> ps ) -> ph ) -> ph )

Syntax hints:   -> wi 4

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-tru 1486  df-fal 1489

This theorem is referenced by: (None)