This is an inofficial mirror of http://metamath.tirix.org for personal testing of a visualizer extension only.
Description: The set of functions between two classes exists if the codomain exists. Generalization of mapex to arbitrary domains. (Contributed by AV, 14-Aug-2024)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | fsetex |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | mapfset | ||
| 2 | ovex | ||
| 3 | 1 2 | eqeltrdi |