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 V , y V f | f : x y

Detailed syntax breakdown

Step Hyp Ref Expression
0 csethom class Set
1 vx setvar x
2 cvv class V
3 vy setvar y
4 vf setvar f
5 4 cv setvar f
6 1 cv setvar x
7 3 cv setvar y
8 6 7 5 wf wff f : x y
9 8 4 cab class f | f : x y
10 1 3 2 2 9 cmpo class x V , y V f | f : x y
11 0 10 wceq wff Set = x V , y V f | f : x y