Radical powers determined by a finite tau-category height #
theorem
MagnitudeConjecture.FiniteTauMatrix.hom_mem_radical_pow_of_height_gap
{C : Type u}
[CategoryTheory.Category.{v, u} C]
[CategoryTheory.Preadditive C]
[CategoryTheory.Limits.HasFiniteBiproducts C]
[CategoryTheory.Limits.HasBinaryBiproducts C]
[CategoryTheory.IsIdempotentComplete C]
{Ind : Type w}
[Fintype Ind]
(T : QuotientSubmoduleEquidistribution.Iyama.FiniteRightTauCategoryData C Ind)
(height : Ind → ℕ)
(hstep : ∀ (y : Ind) (i : Fin (rightMiddleArity T y)), height (rightMiddleLabel T y i) + 1 = height y)
(n : ℕ)
{x y : Ind}
(hgap : height x + n ≤ height y)
(f : T.obj x ⟶ T.obj y)
:
Recursive incoming factorization places every Hom in its height power.
theorem
MagnitudeConjecture.FiniteTauMatrix.radical_pow_eq_zero_of_height_gap
{C : Type u}
[CategoryTheory.Category.{v, u} C]
[CategoryTheory.Preadditive C]
[CategoryTheory.Limits.HasFiniteBiproducts C]
[CategoryTheory.Limits.HasBinaryBiproducts C]
[CategoryTheory.IsIdempotentComplete C]
{Ind : Type w}
[Fintype Ind]
(T : QuotientSubmoduleEquidistribution.Iyama.FiniteRightTauCategoryData C Ind)
(height : Ind → ℕ)
(hh : ∀ {x y : Ind} (f : T.obj x ⟶ T.obj y), f ≠ 0 → ¬CategoryTheory.IsIso f → height x < height y)
(n : ℕ)
{x y : Ind}
(hgap : height y < height x + n)
(f : T.obj x ⟶ T.obj y)
(hf : f ∈ (T.radical.ideal.pow n).hom (T.obj x) (T.obj y))
:
f = 0
Powers beyond the available strict height increase vanish.