Module: Mathlib.CategoryTheory.GradedObject.Monoidal

Goal state before:
pp: I : Type u
inst✝²⁵ : AddMonoid I
C : Type u_1
inst✝²⁴ : Category.{v_1, u_1} C
inst✝²³ : MonoidalCategory C
X₁ X₂ X₃ X₄ : GradedObject I C
inst✝²² : X₁.HasTensor X₂
inst✝²¹ : X₂.HasTensor X₃
inst✝²⁰ : X₃.HasTensor X₄
inst✝¹⁹ : (tensorObj X₁ X₂).HasTensor X₃
inst✝¹⁸ : X₁.HasTensor (tensorObj X₂ X₃)
inst✝¹⁷ : (tensorObj X₂ X₃).HasTensor X₄
inst✝¹⁶ : X₂.HasTensor (tensorObj X₃ X₄)
inst✝¹⁵ : (tensorObj (tensorObj X₁ X₂) X₃).HasTensor X₄
inst✝¹⁴ : (tensorObj X₁ (tensorObj X₂ X₃)).HasTensor X₄
inst✝¹³ : X₁.HasTensor (tensorObj (tensorObj X₂ X₃) X₄)
inst✝¹² : X₁.HasTensor (tensorObj X₂ (tensorObj X₃ X₄))
inst✝¹¹ : (tensorObj X₁ X₂).HasTensor (tensorObj X₃ X₄)
inst✝¹⁰ : X₁.HasGoodTensor₁₂Tensor X₂ X₃
inst✝⁹ : X₁.HasGoodTensorTensor₂₃ X₂ X₃
inst✝⁸ : X₁.HasGoodTensor₁₂Tensor (tensorObj X₂ X₃) X₄
inst✝⁷ : X₁.HasGoodTensorTensor₂₃ (tensorObj X₂ X₃) X₄
inst✝⁶ : X₂.HasGoodTensor₁₂Tensor X₃ X₄
inst✝⁵ : X₂.HasGoodTensorTensor₂₃ X₃ X₄
inst✝⁴ : (tensorObj X₁ X₂).HasGoodTensor₁₂Tensor X₃ X₄
inst✝³ : (tensorObj X₁ X₂).HasGoodTensorTensor₂₃ X₃ X₄
inst✝² : X₁.HasGoodTensor₁₂Tensor X₂ (tensorObj X₃ X₄)
inst✝¹ : X₁.HasGoodTensorTensor₂₃ X₂ (tensorObj X₃ X₄)
inst✝ : X₁.HasTensor₄ObjExt X₂ X₃ X₄
⊢ (associator (tensorObj X₁ X₂) X₃ X₄).inv ≫
      tensorHom (associator X₁ X₂ X₃).hom (𝟙 X₄) ≫
        (associator X₁ (tensorObj X₂ X₃) X₄).hom ≫ tensorHom (𝟙 X₁) (associator X₂ X₃ X₄).hom =
    (associator (tensorObj X₁ X₂) X₃ X₄).inv ≫
      (associator (tensorObj X₁ X₂) X₃ X₄).hom ≫ (associator X₁ X₂ (tensorObj X₃ X₄)).hom

Tactic:
← cancel_epi (associator X₁ X₂ (tensorObj X₃ X₄)).inv,

Goal state after:
I : Type u
inst✝²⁵ : AddMonoid I
C : Type u_1
inst✝²⁴ : Category.{v_1, u_1} C
inst✝²³ : MonoidalCategory C
X₁ X₂ X₃ X₄ : GradedObject I C
inst✝²² : X₁.HasTensor X₂
inst✝²¹ : X₂.HasTensor X₃
inst✝²⁰ : X₃.HasTensor X₄
inst✝¹⁹ : (tensorObj X₁ X₂).HasTensor X₃
inst✝¹⁸ : X₁.HasTensor (tensorObj X₂ X₃)
inst✝¹⁷ : (tensorObj X₂ X₃).HasTensor X₄
inst✝¹⁶ : X₂.HasTensor (tensorObj X₃ X₄)
inst✝¹⁵ : (tensorObj (tensorObj X₁ X₂) X₃).HasTensor X₄
inst✝¹⁴ : (tensorObj X₁ (tensorObj X₂ X₃)).HasTensor X₄
inst✝¹³ : X₁.HasTensor (tensorObj (tensorObj X₂ X₃) X₄)
inst✝¹² : X₁.HasTensor (tensorObj X₂ (tensorObj X₃ X₄))
inst✝¹¹ : (tensorObj X₁ X₂).HasTensor (tensorObj X₃ X₄)
inst✝¹⁰ : X₁.HasGoodTensor₁₂Tensor X₂ X₃
inst✝⁹ : X₁.HasGoodTensorTensor₂₃ X₂ X₃
inst✝⁸ : X₁.HasGoodTensor₁₂Tensor (tensorObj X₂ X₃) X₄
inst✝⁷ : X₁.HasGoodTensorTensor₂₃ (tensorObj X₂ X₃) X₄
inst✝⁶ : X₂.HasGoodTensor₁₂Tensor X₃ X₄
inst✝⁵ : X₂.HasGoodTensorTensor₂₃ X₃ X₄
inst✝⁴ : (tensorObj X₁ X₂).HasGoodTensor₁₂Tensor X₃ X₄
inst✝³ : (tensorObj X₁ X₂).HasGoodTensorTensor₂₃ X₃ X₄
inst✝² : X₁.HasGoodTensor₁₂Tensor X₂ (tensorObj X₃ X₄)
inst✝¹ : X₁.HasGoodTensorTensor₂₃ X₂ (tensorObj X₃ X₄)
inst✝ : X₁.HasTensor₄ObjExt X₂ X₃ X₄
⊢ (associator X₁ X₂ (tensorObj X₃ X₄)).inv ≫
      (associator (tensorObj X₁ X₂) X₃ X₄).inv ≫
        tensorHom (associator X₁ X₂ X₃).hom (𝟙 X₄) ≫
          (associator X₁ (tensorObj X₂ X₃) X₄).hom ≫ tensorHom (𝟙 X₁) (associator X₂ X₃ X₄).hom =
    (associator X₁ X₂ (tensorObj X₃ X₄)).inv ≫
      (associator (tensorObj X₁ X₂) X₃ X₄).inv ≫
        (associator (tensorObj X₁ X₂) X₃ X₄).hom ≫ (associator X₁ X₂ (tensorObj X₃ X₄)).hom