Description: A finite set always belongs to a power class. (Contributed by Glauco Siliprandi, 17-Aug-2020)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | pwfin0 | |- ( ~P A i^i Fin ) =/= (/) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | 0pwfi | |- (/) e. ( ~P A i^i Fin ) |
|
| 2 | ne0i | |- ( (/) e. ( ~P A i^i Fin ) -> ( ~P A i^i Fin ) =/= (/) ) |
|
| 3 | 1 2 | ax-mp | |- ( ~P A i^i Fin ) =/= (/) |