Description: Define the set of functions (morphisms of sets) between two sets. Same as df-map with arguments swapped. TODO: prove the same staple lemmas as for ^m .
Remark: one may define -Set-> = ( x e. dom Struct , y e. dom Struct |-> { f | f : ( Basex ) --> ( Basey ) } ) so that for morphisms between other structures, one could write ... = { f e. ( x -Set-> y ) | ... } .
(Contributed by BJ, 11-Apr-2020)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-bj-sethom | |- -Set-> = ( x e. _V , y e. _V |-> { f | f : x --> y } ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | csethom | |- -Set-> |
|
| 1 | vx | |- x |
|
| 2 | cvv | |- _V |
|
| 3 | vy | |- y |
|
| 4 | vf | |- f |
|
| 5 | 4 | cv | |- f |
| 6 | 1 | cv | |- x |
| 7 | 3 | cv | |- y |
| 8 | 6 7 5 | wf | |- f : x --> y |
| 9 | 8 4 | cab | |- { f | f : x --> y } |
| 10 | 1 3 2 2 9 | cmpo | |- ( x e. _V , y e. _V |-> { f | f : x --> y } ) |
| 11 | 0 10 | wceq | |- -Set-> = ( x e. _V , y e. _V |-> { f | f : x --> y } ) |