Metamath Proof Explorer


Theorem rhmfn

Description: The mapping of two rings to the ring homomorphisms between them is a function. (Contributed by AV, 1-Mar-2020)

Ref Expression
Assertion rhmfn ⊢ RingHom Fn Ring × Ring

Proof

Step Hyp Ref Expression
1 dfrhm2 ⊢ RingHom = r ∈ Ring , s ∈ Ring ⟼ r GrpHom s ∩ mulGrp r MndHom mulGrp s
2 ovex ⊢ r GrpHom s ∈ V
3 2 inex1 ⊢ r GrpHom s ∩ mulGrp r MndHom mulGrp s ∈ V
4 1 3 fnmpoi ⊢ RingHom Fn Ring × Ring