{n m₁ m₂ : ℕ} →
  {f₁ : SimplexCategory.mk n ⟶ SimplexCategory.mk m₁} →
    CategoryTheory.SplitEpi f₁ →
      (SimplexCategory.mk n ⟶ SimplexCategory.mk m₂) → (SimplexCategory.mk m₁ ⟶ SimplexCategory.mk m₂)