Metamath Proof Explorer


Theorem retbwax3

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

Ref Expression
Assertion retbwax3 φ ψ φ φ

Proof

Step Hyp Ref Expression
1 retbwax2 φ φ φ
2 merco1lem7 φ φ φ φ ψ φ φ
3 1 2 ax-mp φ ψ φ φ