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Mathlib.AlgebraicTopology.SimplexCategory.MorphismProperty

Properties of morphisms in the simplex category #

In this file, we show that morphisms in the simplex category are generated by faces and degeneracies. This is stated by saying that if W : MorphismProperty SimplexCategory is multiplicative, and contains faces and degeneracies, then W = ⊤. This statement is deduced from a similar statement for the category SimplexCategory.Truncated d.

theorem SimplexCategory.Truncated.morphismProperty_eq_top {d : ℕ} (W : CategoryTheory.MorphismProperty (Truncated d)) [W.IsMultiplicative] (δ_mem : ∀ (n : ℕ) (hn : n < d) (i : Fin (n + 2)), W (δ d i ⋯ ⋯)) (σ_mem : ∀ (n : ℕ) (hn : n < d) (i : Fin (n + 1)), W (σ d i ⋯ ⋯)) :
W = ⊤
theorem SimplexCategory.morphismProperty_eq_top (W : CategoryTheory.MorphismProperty SimplexCategory) [W.IsMultiplicative] (δ_mem : ∀ {n : ℕ} (i : Fin (n + 2)), W (δ i)) (σ_mem : ∀ {n : ℕ} (i : Fin (n + 1)), W (σ i)) :
W = ⊤