Direct heights increase along nonzero nonisomorphisms #
theorem
MagnitudeConjecture.RightModule.FiniteIndecomposableSkeleton.PrimitiveDirectedBoundaryData.directFactorHeight_lt_of_hom
{k A : Type u}
[Field k]
[Ring A]
[Algebra k A]
[FiniteDimensional k A]
[IsNoetherianRing Aᵐᵒᵖ]
[IsAlgClosed k]
{S : FiniteIndecomposableSkeleton k A}
{K : Set (Fin S.n)}
{D : S.PrimitiveMultiplicityInput K}
(B : S.PrimitiveDirectedBoundaryData D)
{X Y : S.SurvivingLabel K}
(f : S.factorObject K X ⟶ S.factorObject K Y)
(hf : f ≠ 0)
(hn : ¬CategoryTheory.IsIso f)
:
B.directFactorHeight X < B.directFactorHeight Y
Induction through incoming meshes makes the directly constructed height strictly increase on every nonzero nonisomorphism.
theorem
MagnitudeConjecture.RightModule.FiniteIndecomposableSkeleton.PrimitiveDirectedBoundaryData.directFactorHeight_lt_of_ne
{k A : Type u}
[Field k]
[Ring A]
[Algebra k A]
[FiniteDimensional k A]
[IsNoetherianRing Aᵐᵒᵖ]
[IsAlgClosed k]
{S : FiniteIndecomposableSkeleton k A}
{K : Set (Fin S.n)}
{D : S.PrimitiveMultiplicityInput K}
(B : S.PrimitiveDirectedBoundaryData D)
{X Y : S.SurvivingLabel K}
(hXY : X ≠ Y)
(f : S.factorObject K X ⟶ S.factorObject K Y)
(hf : f ≠ 0)
:
B.directFactorHeight X < B.directFactorHeight Y
A nonzero map between distinct selected factor objects increases height.