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Mathlib.Algebra.Homology.Embedding.CochainComplex

Truncations on cochain complexes indexed by the integers. #

In this file, we introduce abbreviations for the canonical truncations CochainComplex.truncLE, CochainComplex.truncGE of cochain complexes indexed by , as well as the conditions CochainComplex.IsStrictlyLE, CochainComplex.IsStrictlyGE, CochainComplex.IsLE, and CochainComplex.IsGE.

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If K : CochainComplex C ℤ, this is the canonical truncation ≤ n of K.

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      If K : CochainComplex C ℤ, this is the canonical truncation ≥ n of K.

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          The morphism K.truncLE n ⟶ L.truncLE n induced by a morphism K ⟶ L.

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              The morphism K.truncGE n ⟶ L.truncGE n induced by a morphism K ⟶ L.

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                  The condition that a cochain complex K is strictly ≥ n.

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                      The condition that a cochain complex K is strictly ≤ n.

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                          The condition that a cochain complex K is (cohomologically) ≥ n.

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                              The condition that a cochain complex K is (cohomologically) ≤ n.

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                                  A cochain complex that is both strictly ≤ n and ≥ n is isomorphic to a complex (single _ _ n).obj M for some object M.

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                                  The cokernel sequence of the monomorphism K.ιTruncLE n.

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                                      noncomputable abbrev CochainComplex.shortComplexTruncLEX₃ToTruncGE {C : Type u_1} [CategoryTheory.Category.{v_1, u_1} C] [CategoryTheory.Abelian C] (K : CochainComplex C ) (n₀ n₁ : ) (h : n₀ + 1 = n₁) :

                                      The canonical morphism (K.shortComplexTruncLE n₀).X₃ ⟶ K.truncGE n₁.

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