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This edge only exists if `{i, a, b}` has cardinality less than `n`. -/
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@[simps]
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- def edge (n : ℕ) (i a b : Fin (n+ 1 )) (hab : a ≤ b) (H : #{i, a, b} ≤ n) :
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+ def edge (n : ℕ) (i a b : Fin (n + 1 )) (hab : a ≤ b) (H : #{i, a, b} ≤ n) :
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(Λ[n, i] : SSet.{u}) _⦋1 ⦌ :=
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⟨stdSimplex.edge n a b hab, by
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have hS : ¬ ({i, a, b} = Finset.univ) := fun hS ↦ by
@@ -119,7 +119,7 @@ def edge (n : ℕ) (i a b : Fin (n+1)) (hab : a ≤ b) (H : #{i, a, b} ≤ n) :
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/-- Alternative constructor for the edge of `Λ[n, i]` with endpoints `a` and `b`,
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assuming `3 ≤ n`. -/
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@[simps!]
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- def edge₃ (n : ℕ) (i a b : Fin (n+ 1 )) (hab : a ≤ b) (H : 3 ≤ n) :
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+ def edge₃ (n : ℕ) (i a b : Fin (n + 1 )) (hab : a ≤ b) (H : 3 ≤ n) :
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(Λ[n, i] : SSet.{u}) _⦋1 ⦌ :=
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edge n i a b hab <| Finset.card_le_three.trans H
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@@ -128,7 +128,7 @@ def edge₃ (n : ℕ) (i a b : Fin (n+1)) (hab : a ≤ b) (H : 3 ≤ n) :
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This constructor assumes `0 < i < n`,
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which is the type of horn that occurs in the horn-filling condition of quasicategories. -/
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@[simps!]
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- def primitiveEdge {n : ℕ} {i : Fin (n+ 1 )}
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+ def primitiveEdge {n : ℕ} {i : Fin (n + 1 )}
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(h₀ : 0 < i) (hₙ : i < Fin.last n) (j : Fin n) :
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(Λ[n, i] : SSet.{u}) _⦋1 ⦌ := by
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refine edge n i j.castSucc j.succ ?_ ?_
@@ -144,9 +144,9 @@ def primitiveEdge {n : ℕ} {i : Fin (n+1)}
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This constructor assumes `0 < i < n`,
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which is the type of horn that occurs in the horn-filling condition of quasicategories. -/
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@[simps]
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- def primitiveTriangle {n : ℕ} (i : Fin (n+ 4 ))
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- (h₀ : 0 < i) (hₙ : i < Fin.last (n+ 3 ))
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- (k : ℕ) (h : k < n+ 2 ) : (Λ[n+3 , i] : SSet.{u}) _⦋2 ⦌ := by
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+ def primitiveTriangle {n : ℕ} (i : Fin (n + 4 ))
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+ (h₀ : 0 < i) (hₙ : i < Fin.last (n + 3 ))
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+ (k : ℕ) (h : k < n + 2 ) : (Λ[n+3 , i] : SSet.{u}) _⦋2 ⦌ := by
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refine ⟨stdSimplex.triangle
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(n := n+3 ) ⟨k, by omega⟩ ⟨k+1 , by omega⟩ ⟨k+2 , by omega⟩ ?_ ?_, ?_⟩
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· simp only [Fin.mk_le_mk, le_add_iff_nonneg_right, zero_le]
@@ -185,7 +185,7 @@ def primitiveTriangle {n : ℕ} (i : Fin (n+4))
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· exact Ne.symm hl.2 .2 .2
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/-- The `j`th face of codimension `1` of the `i`-th horn. -/
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- def face {n : ℕ} (i j : Fin (n+ 2 )) (h : j ≠ i) : (Λ[n+1 , i] : SSet.{u}) _⦋n⦌ :=
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+ def face {n : ℕ} (i j : Fin (n + 2 )) (h : j ≠ i) : (Λ[n+1 , i] : SSet.{u}) _⦋n⦌ :=
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yonedaEquiv (Subpresheaf.lift (stdSimplex.δ j) (by
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simpa using face_le_horn _ _ h))
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