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 ) =/= (/) |