(R : Type u) →
  {ι : Type v} →
    [inst : Ring R] →
      [inst_1 : Fintype ι] →
        [inst_2 : DecidableEq ι] →
          (i : ι) →
            (ModuleCat.toMatrixModCat R ι).comp (MatrixModCat.toModuleCat R i) ≅ CategoryTheory.Functor.id (ModuleCat R)