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 ⊢ 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 ∈ V , 𝑦 ∈ V ↦ { 𝑓 ∣ 𝑓 : 𝑥 ⟶ 𝑦 } )
11 0 10 wceq ⊢ Set⟶ = ( 𝑥 ∈ V , 𝑦 ∈ V ↦ { 𝑓 ∣ 𝑓 : 𝑥 ⟶ 𝑦 } )