Description: Alternate proof of vtoclgf . Proof from vtoclgft . (This may have been the original proof before shortening.) (Contributed by BJ, 30-Sep-2019) (Proof modification is discouraged.) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | bj-vtoclgfALT.1 | |- F/_ x A | |
| bj-vtoclgfALT.2 | |- F/ x ps | ||
| bj-vtoclgfALT.3 | |- ( x = A -> ( ph <-> ps ) ) | ||
| bj-vtoclgfALT.4 | |- ph | ||
| Assertion | bj-vtoclgfALT | |- ( A e. V -> ps ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | bj-vtoclgfALT.1 | |- F/_ x A | |
| 2 | bj-vtoclgfALT.2 | |- F/ x ps | |
| 3 | bj-vtoclgfALT.3 | |- ( x = A -> ( ph <-> ps ) ) | |
| 4 | bj-vtoclgfALT.4 | |- ph | |
| 5 | 1 2 | pm3.2i | |- ( F/_ x A /\ F/ x ps ) | 
| 6 | 3 | ax-gen | |- A. x ( x = A -> ( ph <-> ps ) ) | 
| 7 | 4 | ax-gen | |- A. x ph | 
| 8 | 6 7 | pm3.2i | |- ( A. x ( x = A -> ( ph <-> ps ) ) /\ A. x ph ) | 
| 9 | vtoclgft | |- ( ( ( F/_ x A /\ F/ x ps ) /\ ( A. x ( x = A -> ( ph <-> ps ) ) /\ A. x ph ) /\ A e. V ) -> ps ) | |
| 10 | 5 8 9 | mp3an12 | |- ( A e. V -> ps ) |