∀ {R : Type u} {S : Type v} {ι : Type w} [inst : CommRing R] [inst_1 : CommRing S] [inst_2 : Algebra R S] (val : ι → S)
  (h : Function.Surjective ⇑(MvPolynomial.aeval val)),
  Algebra.Generators.ofSurjective val h = { val := val, σ' := fun x => ⋯.choose, aeval_val_σ' := ⋯, algebraMap_eq := ⋯ }