Theorem retbwax3 1488

Description: tbw-ax3 1467 rederived from merco1 1478. (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 1481	. 2 |- (ph -> (ph -> ph))
2		merco1lem7 1487	. 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 177  df-tru 1319  df-fal 1320

This theorem is referenced by: (None)