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Mathlib.Tactic.CategoryTheory.Monoidal.PureCoherence

Coherence tactic for monoidal categories #

We provide a monoidal_coherence tactic, which proves that any two morphisms (with the same source and target) in a monoidal category which are built out of associators and unitors are equal.

theorem Mathlib.Tactic.Monoidal.mk_eq_of_naturality {C : Type u} [CategoryTheory.Category.{v, u} C] [CategoryTheory.MonoidalCategory C] {f g f' : C} {η θ : f g} {η' θ' : f g} (η_f : CategoryTheory.MonoidalCategory.tensorObj (𝟙_ C) f f') (η_g : CategoryTheory.MonoidalCategory.tensorObj (𝟙_ C) g f') (η_hom : η'.hom = η) (Θ_hom : θ'.hom = θ) (Hη : CategoryTheory.MonoidalCategory.whiskerLeftIso (𝟙_ C) η' ≪≫ η_g = η_f) (Hθ : CategoryTheory.MonoidalCategory.whiskerLeftIso (𝟙_ C) θ' ≪≫ η_g = η_f) :
η = θ

Close the goal of the form η = θ, where η and θ are 2-isomorphisms made up only of associators, unitors, and identities.

example {C : Type} [Category C] [MonoidalCategory C] :
  (λ_ (𝟙_ C)).hom = (ρ_ (𝟙_ C)).hom := by
  monoidal_coherence
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    Close the goal of the form η = θ, where η and θ are 2-isomorphisms made up only of associators, unitors, and identities.

    example {C : Type} [Category C] [MonoidalCategory C] :
      (λ_ (𝟙_ C)).hom = (ρ_ (𝟙_ C)).hom := by
      monoidal_coherence
    
    Equations
    Instances For