{P : Sort u} →
  {name : Lean.Name} →
    {color : String} →
      {subcategories : Array String} →
        {name' : Lean.Name} →
          {color' : String} →
            {subcategories' : Array String} →
              { name := name, color := color, subcategories := subcategories } =
                  { name := name', color := color', subcategories := subcategories' } →
                (name = name' → color = color' → subcategories = subcategories' → P) → P