One simple algebra splits the whole category #
Splitting the single object X ⊞ Xᘁ and passing to a simple
quotient gives an algebra that splits the tensor generator and its
dual, a direct summand being a subquotient. The split objects are
closed under sums and tensor products, so they contain every mixed
power, and over a simple algebra they are closed under subquotients
as well (RS.exists_mix_of_isSubquotient), so finite tensor
generation carries them to every object. The scalars of that
algebra are the complex numbers, so its Γ-algebra has a complex
point.
theorem
RS.exists_splitting_simple_algebra
{C : Type v}
[CategoryTheory.SmallCategory C]
[CategoryTheory.MonoidalCategory C]
[CategoryTheory.SymmetricCategory C]
[CategoryTheory.Abelian C]
[CategoryTheory.RigidCategory C]
[CategoryTheory.MonoidalPreadditive C]
[CategoryTheory.Limits.HasFiniteBiproducts C]
(ψ : ℂ ≃+* CategoryTheory.End (CategoryTheory.MonoidalCategoryStruct.tensorUnit C))
(P : SchurPackage)
(P₀ : SchurPackage)
(L : OddLine (CategoryTheory.Ind C))
(X : C)
(hgen : TensorGeneratedBy C X)
(hgrow : ModerateLengthGrowth C)
(hlen : ∀ (Z : C), ∃ (N : ℕ), LengthLE Z N)
:
∃ (𝔹 : CategoryTheory.Ind C) (x : CategoryTheory.MonObj 𝔹) (x_1 : CategoryTheory.IsCommMonObj 𝔹),
CategoryTheory.MonObj.one ≠ 0 ∧ (∀ (I : CategoryTheory.Subobject 𝔹), IsIdeal 𝔹 I → I = ⊥ ∨ I = ⊤) ∧ SplitsOn L 𝔹 indOf ∧ Nonempty (SuperPoint (gammaAlgebra (CategoryTheory.Ind C) L 𝔹))
One simple algebra splits everything, and its Γ-algebra has a complex point.