Triangulated Categories #
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This file contains the definition of triangulated categories, which are pretriangulated categories which satisfy the octahedron axiom.
- m₁ : Z₁₂ ⟶ Z₁₃
- m₃ : Z₁₃ ⟶ Z₂₃
- comm₁ : v₁₂ ≫ self.m₁ = u₂₃ ≫ v₁₃
- comm₂ : self.m₁ ≫ w₁₃ = w₁₂
- comm₃ : v₁₃ ≫ self.m₃ = v₂₃
- comm₄ : w₁₃ ≫ (category_theory.shift_functor C 1).map u₁₂ = self.m₃ ≫ w₂₃
- mem : category_theory.pretriangulated.triangle.mk self.m₁ self.m₃ (w₂₃ ≫ (category_theory.shift_functor C 1).map v₁₂) ∈ dist_triang C
An octahedron is a type of datum whose existence is asserted by the octahedron axiom (TR 4), see https://stacks.math.columbia.edu/tag/05QK
Instances for category_theory.triangulated.octahedron
- category_theory.triangulated.octahedron.has_sizeof_inst
- category_theory.triangulated.octahedron.nonempty
The triangle Z₁₂ ⟶ Z₁₃ ⟶ Z₂₃ ⟶ Z₁₂⟦1⟧
given by an octahedron.
Equations
- h.triangle = category_theory.pretriangulated.triangle.mk h.m₁ h.m₃ (w₂₃ ≫ (category_theory.shift_functor C 1).map v₁₂)
The first morphism of triangles given by an octahedron.
The second morphism of triangles given an octahedron.
- octahedron_axiom : ∀ ⦃X₁ X₂ X₃ Z₁₂ Z₂₃ Z₁₃ : C⦄ ⦃u₁₂ : X₁ ⟶ X₂⦄ ⦃u₂₃ : X₂ ⟶ X₃⦄ ⦃u₁₃ : X₁ ⟶ X₃⦄ (comm : u₁₂ ≫ u₂₃ = u₁₃) ⦃v₁₂ : X₂ ⟶ Z₁₂⦄ ⦃w₁₂ : Z₁₂ ⟶ (category_theory.shift_functor C 1).obj X₁⦄ (h₁₂ : category_theory.pretriangulated.triangle.mk u₁₂ v₁₂ w₁₂ ∈ dist_triang C) ⦃v₂₃ : X₃ ⟶ Z₂₃⦄ ⦃w₂₃ : Z₂₃ ⟶ (category_theory.shift_functor C 1).obj X₂⦄ (h₂₃ : category_theory.pretriangulated.triangle.mk u₂₃ v₂₃ w₂₃ ∈ dist_triang C) ⦃v₁₃ : X₃ ⟶ Z₁₃⦄ ⦃w₁₃ : Z₁₃ ⟶ (category_theory.shift_functor C 1).obj X₁⦄ (h₁₃ : category_theory.pretriangulated.triangle.mk u₁₃ v₁₃ w₁₃ ∈ dist_triang C), nonempty (category_theory.triangulated.octahedron comm h₁₂ h₂₃ h₁₃)
A triangulated category is a pretriangulated category which satisfies the octahedron axiom (TR 4), see https://stacks.math.columbia.edu/tag/05QK
Instances for category_theory.is_triangulated
- category_theory.is_triangulated.has_sizeof_inst
A choice of octahedron given by the octahedron axiom.
Equations
- category_theory.triangulated.some_octahedron comm h₁₂ h₂₃ h₁₃ = _.some