Metamath Proof Explorer


Definition df-bj-sethom

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 } )

Detailed syntax breakdown

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 } )