Description: tbw-ax4 rederived from merco1 . (Contributed by Anthony Hart, 17-Sep-2011) (Proof modification is discouraged.) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | retbwax4 | |- ( F. -> ph ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | merco1lem1 | |- ( ph -> ( F. -> ph ) ) |
|
| 2 | merco1lem1 | |- ( ( ph -> ( F. -> ph ) ) -> ( F. -> ph ) ) |
|
| 3 | 1 2 | ax-mp | |- ( F. -> ph ) |