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DerivedAlgGeo.CategoryTheory.Triangulated.StabilityCondition.Foundation.Deformation.PullbackCokernel

Pullback and cokernel transport in an owner thin interval #

Strict subobjects of a strict quotient pull back to strict subobjects. Their cokernels agree up to isomorphism, so the perturbed charge and phase transport across the pullback square. These are the categorical and phase-theoretic inputs for strict maximal destabilizing quotient selection.

Pulling back a strict epimorphism along an interval subobject preserves strict epimorphy of the pullback projection.

A kernel followed by a strict epimorphism is an owner strict short exact sequence in a thin interval.

theorem CategoryTheory.Triangulated.WeakStabilityCondition.StabilityCondition.Deformation.Slicing.IntervalCat.strictShortExact_pullback_left (C : Type u) [Category.{v, u} C] [Limits.HasZeroObject C] [HasShift C ℤ] [Preadditive C] [∀ (n : ℤ), (shiftFunctor C n).Additive] [Pretriangulated C] [IsTriangulated C] {s : Slicing C} {a b : ℝ} [Fact (a < b)] [Fact (b - a ≤ 1)] {K E Q : Slicing.IntervalCat C s a b} {i : K ⟶ E} {q : E ⟶ Q} (hiq : CategoryStruct.comp i q = 0) (hKer : Limits.IsLimit (Limits.KernelFork.ofι i hiq)) (hq : IsStrictEpi q) (B : Subobject Q) :
let pb := (Subobject.pullback q).obj B; let m := have hiB := ⋯; pb.factorThru i ⋯; StrictShortExact { X₁ := K, X₂ := Subobject.underlying.obj pb, X₃ := Subobject.underlying.obj B, f := m, g := Subobject.pullbackπ q B, zero := ⋯ }

Pulling a kernel--strict-epimorphism sequence back along an interval subobject preserves owner strict short exactness.

theorem CategoryTheory.Triangulated.WeakStabilityCondition.StabilityCondition.Deformation.Slicing.IntervalCat.strictShortExact_pullback_right (C : Type u) [Category.{v, u} C] [Limits.HasZeroObject C] [HasShift C ℤ] [Preadditive C] [∀ (n : ℤ), (shiftFunctor C n).Additive] [Pretriangulated C] [IsTriangulated C] {s : Slicing C} {a b : ℝ} [Fact (a < b)] [Fact (b - a ≤ 1)] {E Q Y : Slicing.IntervalCat C s a b} (q : E ⟶ Q) (hq : IsStrictEpi q) (B : Subobject Q) (g : Q ⟶ Y) (hBg : CategoryStruct.comp B.arrow g = 0) (hBKer : Limits.IsLimit (Limits.KernelFork.ofι B.arrow hBg)) (hg : IsStrictEpi g) :
let pb := (Subobject.pullback q).obj B; let p := CategoryStruct.comp q g; StrictShortExact { X₁ := Subobject.underlying.obj pb, X₂ := E, X₃ := Y, f := pb.arrow, g := p, zero := ⋯ }

The complementary pullback sequence associated to two composable strict epimorphisms is owner strict short exact.

Pulling back a strict interval subobject preserves strictness of its canonical arrow.

A kernel subobject lies below the pullback of every subobject of its canonical cokernel.

A nonzero subobject of a cokernel pulls back to a strict enlargement of the kernel subobject.

A strict proper subobject of a cokernel cannot pull back to the top subobject.

Pulling back a strict subobject along a cokernel projection preserves its cokernel object up to canonical isomorphism.

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Instances For
    theorem CategoryTheory.Triangulated.WeakStabilityCondition.StabilityCondition.Deformation.SkewedStabilityFunction.phase_cokernel_lt_of_phase_gt_strictSubobject (C : Type u) [Category.{v, u} C] [Limits.HasZeroObject C] [HasShift C ℤ] [Preadditive C] [∀ (n : ℤ), (shiftFunctor C n).Additive] [Pretriangulated C] [IsTriangulated C] {Λ : Type u'} [AddCommGroup Λ] {κ : K₀ C →+ Λ} {σ : StabilityCondition.WithClassMap C κ} {a b : ℝ} {F : SkewedStabilityFunction C κ σ.slicing a b} [Fact (a < b)] [Fact (b - a ≤ 1)] {Y : Slicing.IntervalCat C σ.slicing a b} {A : Subobject Y} (hAne : A ≠ ⊥) (hAtop : A ≠ ⊤) (hAstrict : IsStrictMono A.arrow) (hAphase : F.phase Y.obj < F.phase (Subobject.underlying.obj A).obj) (hCharge : ∀ {E : C}, Slicing.intervalProp C σ.slicing a b E → ¬Limits.IsZero E → F.ChargeNe E) {L U : ℝ} (hWindow : ∀ (Z : Slicing.IntervalCat C σ.slicing a b), ¬Limits.IsZero Z.obj → L < F.phase Z.obj ∧ F.phase Z.obj < U) (hWidth : U - L < 1) :

    In a common phase window of width less than one, the cokernel of an above-phase proper strict subobject has phase strictly below the original object.