Vanishing when every nonzero morphism is invertible #
theorem
MagnitudeConjecture.CategoricalIrreducible.radical_eq_bot_of_nonzero_isIso
(k : Type u)
[Field k]
{C : Type v}
[CategoryTheory.Category.{w, v} C]
[CategoryTheory.Preadditive C]
[CategoryTheory.Linear k C]
(X Y : C)
(h : ∀ (f : X ⟶ Y), f ≠ 0 → CategoryTheory.IsIso f)
:
radical k X Y = ⊥
A Hom space with only invertible nonzero morphisms has zero radical.
theorem
MagnitudeConjecture.CategoricalIrreducible.finrank_eq_zero_of_radical_eq_bot
(k : Type u)
[Field k]
{C : Type v}
[CategoryTheory.Category.{w, v} C]
[CategoryTheory.Preadditive C]
[CategoryTheory.Linear k C]
(X Y : C)
(h : radical k X Y = ⊥)
:
Module.finrank k (Space k X Y) = 0
A zero radical numerator has zero irreducible quotient dimension.