Description: A function with a finite domain is always finitely supported. (Contributed by AV, 25-May-2019)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | fndmfisuppfi.f | |- ( ph -> F Fn D ) | |
| fndmfisuppfi.d | |- ( ph -> D e. Fin ) | ||
| fndmfisuppfi.z | |- ( ph -> Z e. V ) | ||
| Assertion | fndmfifsupp | |- ( ph -> F finSupp Z ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | fndmfisuppfi.f | |- ( ph -> F Fn D ) | |
| 2 | fndmfisuppfi.d | |- ( ph -> D e. Fin ) | |
| 3 | fndmfisuppfi.z | |- ( ph -> Z e. V ) | |
| 4 | dffn3 | |- ( F Fn D <-> F : D --> ran F ) | |
| 5 | 1 4 | sylib | |- ( ph -> F : D --> ran F ) | 
| 6 | 5 2 3 | fdmfifsupp | |- ( ph -> F finSupp Z ) |