Description: A function is a function on its domain. (Contributed by Glauco Siliprandi, 23-Oct-2021)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | funfnd.1 | |- ( ph -> Fun A ) |
|
| Assertion | funfnd | |- ( ph -> A Fn dom A ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | funfnd.1 | |- ( ph -> Fun A ) |
|
| 2 | funfn | |- ( Fun A <-> A Fn dom A ) |
|
| 3 | 1 2 | sylib | |- ( ph -> A Fn dom A ) |