Theorem retbwax4 1640

Description: tbw-ax4 1628 rederived from merco1 1638. (Contributed by Anthony Hart, 17-Sep-2011.) (Proof modification is discouraged.) (New usage is discouraged.)

Assertion

Ref	Expression
retbwax4	|- ( F. -> ph )

Proof of Theorem retbwax4

Step	Hyp	Ref	Expression
1		merco1lem1 1639	. 2 |- ( ph -> ( F. -> ph ) )
2		merco1lem1 1639	. 2 |- ( ( ph -> ( F. -> ph ) ) -> ( F. -> ph ) )
3	1, 2	ax-mp 5	1 |- ( F. -> ph )

Syntax hints:   -> wi 4   F. wfal 1488

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)