HepLean Documentation

Mathlib.Data.Matrix.Defs

Matrices #

This file defines basic properties of matrices up to the module structure.

Matrices with rows indexed by m, columns indexed by n, and entries of type α are represented with Matrix m n α. For the typical approach of counting rows and columns, Matrix (Fin m) (Fin n) α can be used.

Main definitions #

Notation #

The locale Matrix gives the following notation:

See Mathlib/Data/Matrix/ConjTranspose.lean for

Implementation notes #

For convenience, Matrix m n α is defined as m → n → α, as this allows elements of the matrix to be accessed with A i j. However, it is not advisable to construct matrices using terms of the form fun i j ↦ _ or even (fun i j ↦ _ : Matrix m n α), as these are not recognized by Lean as having the right type. Instead, Matrix.of should be used.

def Matrix (m : Type u) (n : Type u') (α : Type v) :
Type (max u u' v)

Matrix m n R is the type of matrices with entries in R, whose rows are indexed by m and whose columns are indexed by n.

Equations
Instances For
    theorem Matrix.ext_iff {m : Type u_2} {n : Type u_3} {α : Type v} {M N : Matrix m n α} :
    (∀ (i : m) (j : n), M i j = N i j) M = N
    theorem Matrix.ext {m : Type u_2} {n : Type u_3} {α : Type v} {M N : Matrix m n α} :
    (∀ (i : m) (j : n), M i j = N i j)M = N
    def Matrix.of {m : Type u_2} {n : Type u_3} {α : Type v} :
    (mnα) Matrix m n α

    Cast a function into a matrix.

    The two sides of the equivalence are definitionally equal types. We want to use an explicit cast to distinguish the types because Matrix has different instances to pi types (such as Pi.mul, which performs elementwise multiplication, vs Matrix.mul).

    If you are defining a matrix, in terms of its entries, use of (fun i j ↦ _). The purpose of this approach is to ensure that terms of the form (fun i j ↦ _) * (fun i j ↦ _) do not appear, as the type of * can be misleading.

    Porting note: In Lean 3, it is also safe to use pattern matching in a definition as | i j := _, which can only be unfolded when fully-applied. https://github.com/leanprover/lean4/issues/2042 means this does not (currently) work in Lean 4.

    Equations
    Instances For
      @[simp]
      theorem Matrix.of_apply {m : Type u_2} {n : Type u_3} {α : Type v} (f : mnα) (i : m) (j : n) :
      Matrix.of f i j = f i j
      @[simp]
      theorem Matrix.of_symm_apply {m : Type u_2} {n : Type u_3} {α : Type v} (f : Matrix m n α) (i : m) (j : n) :
      Matrix.of.symm f i j = f i j
      def Matrix.map {m : Type u_2} {n : Type u_3} {α : Type v} {β : Type w} (M : Matrix m n α) (f : αβ) :
      Matrix m n β

      M.map f is the matrix obtained by applying f to each entry of the matrix M.

      This is available in bundled forms as:

      • AddMonoidHom.mapMatrix
      • LinearMap.mapMatrix
      • RingHom.mapMatrix
      • AlgHom.mapMatrix
      • Equiv.mapMatrix
      • AddEquiv.mapMatrix
      • LinearEquiv.mapMatrix
      • RingEquiv.mapMatrix
      • AlgEquiv.mapMatrix
      Equations
      • M.map f = Matrix.of fun (i : m) (j : n) => f (M i j)
      Instances For
        @[simp]
        theorem Matrix.map_apply {m : Type u_2} {n : Type u_3} {α : Type v} {β : Type w} {M : Matrix m n α} {f : αβ} {i : m} {j : n} :
        M.map f i j = f (M i j)
        @[simp]
        theorem Matrix.map_id {m : Type u_2} {n : Type u_3} {α : Type v} (M : Matrix m n α) :
        M.map id = M
        @[simp]
        theorem Matrix.map_id' {m : Type u_2} {n : Type u_3} {α : Type v} (M : Matrix m n α) :
        (M.map fun (x : α) => x) = M
        @[simp]
        theorem Matrix.map_map {m : Type u_2} {n : Type u_3} {α : Type v} {M : Matrix m n α} {β : Type u_10} {γ : Type u_11} {f : αβ} {g : βγ} :
        (M.map f).map g = M.map (g f)
        theorem Matrix.map_injective {m : Type u_2} {n : Type u_3} {α : Type v} {β : Type w} {f : αβ} (hf : Function.Injective f) :
        Function.Injective fun (M : Matrix m n α) => M.map f
        def Matrix.transpose {m : Type u_2} {n : Type u_3} {α : Type v} (M : Matrix m n α) :
        Matrix n m α

        The transpose of a matrix.

        Equations
        • M.transpose = Matrix.of fun (x : n) (y : m) => M y x
        Instances For
          @[simp]
          theorem Matrix.transpose_apply {m : Type u_2} {n : Type u_3} {α : Type v} (M : Matrix m n α) (i : n) (j : m) :
          M.transpose i j = M j i

          The transpose of a matrix.

          Equations
          Instances For
            instance Matrix.inhabited {m : Type u_2} {n : Type u_3} {α : Type v} [Inhabited α] :
            Inhabited (Matrix m n α)
            Equations
            instance Matrix.add {m : Type u_2} {n : Type u_3} {α : Type v} [Add α] :
            Add (Matrix m n α)
            Equations
            • Matrix.add = Pi.instAdd
            instance Matrix.addSemigroup {m : Type u_2} {n : Type u_3} {α : Type v} [AddSemigroup α] :
            Equations
            • Matrix.addSemigroup = Pi.addSemigroup
            instance Matrix.addCommSemigroup {m : Type u_2} {n : Type u_3} {α : Type v} [AddCommSemigroup α] :
            Equations
            • Matrix.addCommSemigroup = Pi.addCommSemigroup
            instance Matrix.zero {m : Type u_2} {n : Type u_3} {α : Type v} [Zero α] :
            Zero (Matrix m n α)
            Equations
            • Matrix.zero = Pi.instZero
            instance Matrix.addZeroClass {m : Type u_2} {n : Type u_3} {α : Type v} [AddZeroClass α] :
            Equations
            • Matrix.addZeroClass = Pi.addZeroClass
            instance Matrix.addMonoid {m : Type u_2} {n : Type u_3} {α : Type v} [AddMonoid α] :
            AddMonoid (Matrix m n α)
            Equations
            • Matrix.addMonoid = Pi.addMonoid
            instance Matrix.addCommMonoid {m : Type u_2} {n : Type u_3} {α : Type v} [AddCommMonoid α] :
            Equations
            • Matrix.addCommMonoid = Pi.addCommMonoid
            instance Matrix.neg {m : Type u_2} {n : Type u_3} {α : Type v} [Neg α] :
            Neg (Matrix m n α)
            Equations
            • Matrix.neg = Pi.instNeg
            instance Matrix.sub {m : Type u_2} {n : Type u_3} {α : Type v} [Sub α] :
            Sub (Matrix m n α)
            Equations
            • Matrix.sub = Pi.instSub
            instance Matrix.addGroup {m : Type u_2} {n : Type u_3} {α : Type v} [AddGroup α] :
            AddGroup (Matrix m n α)
            Equations
            • Matrix.addGroup = Pi.addGroup
            instance Matrix.addCommGroup {m : Type u_2} {n : Type u_3} {α : Type v} [AddCommGroup α] :
            Equations
            • Matrix.addCommGroup = Pi.addCommGroup
            instance Matrix.unique {m : Type u_2} {n : Type u_3} {α : Type v} [Unique α] :
            Unique (Matrix m n α)
            Equations
            • Matrix.unique = Pi.unique
            instance Matrix.subsingleton {m : Type u_2} {n : Type u_3} {α : Type v} [Subsingleton α] :
            Equations
            • =
            instance Matrix.nonempty {m : Type u_2} {n : Type u_3} {α : Type v} [Nonempty m] [Nonempty n] [Nontrivial α] :
            Equations
            • =
            instance Matrix.smul {m : Type u_2} {n : Type u_3} {R : Type u_7} {α : Type v} [SMul R α] :
            SMul R (Matrix m n α)
            Equations
            • Matrix.smul = Pi.instSMul
            instance Matrix.smulCommClass {m : Type u_2} {n : Type u_3} {R : Type u_7} {S : Type u_8} {α : Type v} [SMul R α] [SMul S α] [SMulCommClass R S α] :
            SMulCommClass R S (Matrix m n α)
            Equations
            • =
            instance Matrix.isScalarTower {m : Type u_2} {n : Type u_3} {R : Type u_7} {S : Type u_8} {α : Type v} [SMul R S] [SMul R α] [SMul S α] [IsScalarTower R S α] :
            IsScalarTower R S (Matrix m n α)
            Equations
            • =
            instance Matrix.isCentralScalar {m : Type u_2} {n : Type u_3} {R : Type u_7} {α : Type v} [SMul R α] [SMul Rᵐᵒᵖ α] [IsCentralScalar R α] :
            Equations
            • =
            instance Matrix.mulAction {m : Type u_2} {n : Type u_3} {R : Type u_7} {α : Type v} [Monoid R] [MulAction R α] :
            MulAction R (Matrix m n α)
            Equations
            instance Matrix.distribMulAction {m : Type u_2} {n : Type u_3} {R : Type u_7} {α : Type v} [Monoid R] [AddMonoid α] [DistribMulAction R α] :
            Equations
            instance Matrix.module {m : Type u_2} {n : Type u_3} {R : Type u_7} {α : Type v} [Semiring R] [AddCommMonoid α] [Module R α] :
            Module R (Matrix m n α)
            Equations
            • Matrix.module = Pi.module m (fun (a : m) => nα) R
            @[simp]
            theorem Matrix.zero_apply {m : Type u_2} {n : Type u_3} {α : Type v} [Zero α] (i : m) (j : n) :
            0 i j = 0
            @[simp]
            theorem Matrix.add_apply {m : Type u_2} {n : Type u_3} {α : Type v} [Add α] (A B : Matrix m n α) (i : m) (j : n) :
            (A + B) i j = A i j + B i j
            @[simp]
            theorem Matrix.smul_apply {m : Type u_2} {n : Type u_3} {α : Type v} {β : Type w} [SMul β α] (r : β) (A : Matrix m n α) (i : m) (j : n) :
            (r A) i j = r A i j
            @[simp]
            theorem Matrix.sub_apply {m : Type u_2} {n : Type u_3} {α : Type v} [Sub α] (A B : Matrix m n α) (i : m) (j : n) :
            (A - B) i j = A i j - B i j
            @[simp]
            theorem Matrix.neg_apply {m : Type u_2} {n : Type u_3} {α : Type v} [Neg α] (A : Matrix m n α) (i : m) (j : n) :
            (-A) i j = -A i j

            simp-normal form pulls of to the outside.

            @[simp]
            theorem Matrix.of_zero {m : Type u_2} {n : Type u_3} {α : Type v} [Zero α] :
            Matrix.of 0 = 0
            @[simp]
            theorem Matrix.of_add_of {m : Type u_2} {n : Type u_3} {α : Type v} [Add α] (f g : mnα) :
            Matrix.of f + Matrix.of g = Matrix.of (f + g)
            @[simp]
            theorem Matrix.of_sub_of {m : Type u_2} {n : Type u_3} {α : Type v} [Sub α] (f g : mnα) :
            Matrix.of f - Matrix.of g = Matrix.of (f - g)
            @[simp]
            theorem Matrix.neg_of {m : Type u_2} {n : Type u_3} {α : Type v} [Neg α] (f : mnα) :
            -Matrix.of f = Matrix.of (-f)
            @[simp]
            theorem Matrix.smul_of {m : Type u_2} {n : Type u_3} {R : Type u_7} {α : Type v} [SMul R α] (r : R) (f : mnα) :
            r Matrix.of f = Matrix.of (r f)
            @[simp]
            theorem Matrix.map_zero {m : Type u_2} {n : Type u_3} {α : Type v} {β : Type w} [Zero α] [Zero β] (f : αβ) (h : f 0 = 0) :
            theorem Matrix.map_add {m : Type u_2} {n : Type u_3} {α : Type v} {β : Type w} [Add α] [Add β] (f : αβ) (hf : ∀ (a₁ a₂ : α), f (a₁ + a₂) = f a₁ + f a₂) (M N : Matrix m n α) :
            (M + N).map f = M.map f + N.map f
            theorem Matrix.map_sub {m : Type u_2} {n : Type u_3} {α : Type v} {β : Type w} [Sub α] [Sub β] (f : αβ) (hf : ∀ (a₁ a₂ : α), f (a₁ - a₂) = f a₁ - f a₂) (M N : Matrix m n α) :
            (M - N).map f = M.map f - N.map f
            theorem Matrix.map_smul {m : Type u_2} {n : Type u_3} {R : Type u_7} {α : Type v} {β : Type w} [SMul R α] [SMul R β] (f : αβ) (r : R) (hf : ∀ (a : α), f (r a) = r f a) (M : Matrix m n α) :
            (r M).map f = r M.map f
            theorem Matrix.map_smul' {n : Type u_3} {α : Type v} {β : Type w} [Mul α] [Mul β] (f : αβ) (r : α) (A : Matrix n n α) (hf : ∀ (a₁ a₂ : α), f (a₁ * a₂) = f a₁ * f a₂) :
            (r A).map f = f r A.map f

            The scalar action via Mul.toSMul is transformed by the same map as the elements of the matrix, when f preserves multiplication.

            theorem Matrix.map_op_smul' {n : Type u_3} {α : Type v} {β : Type w} [Mul α] [Mul β] (f : αβ) (r : α) (A : Matrix n n α) (hf : ∀ (a₁ a₂ : α), f (a₁ * a₂) = f a₁ * f a₂) :
            (MulOpposite.op r A).map f = MulOpposite.op (f r) A.map f

            The scalar action via mul.toOppositeSMul is transformed by the same map as the elements of the matrix, when f preserves multiplication.

            theorem IsSMulRegular.matrix {m : Type u_2} {n : Type u_3} {R : Type u_7} {S : Type u_8} [SMul R S] {k : R} (hk : IsSMulRegular S k) :
            theorem IsLeftRegular.matrix {m : Type u_2} {n : Type u_3} {α : Type v} [Mul α] {k : α} (hk : IsLeftRegular k) :
            instance Matrix.subsingleton_of_empty_left {m : Type u_2} {n : Type u_3} {α : Type v} [IsEmpty m] :
            Equations
            • =
            instance Matrix.subsingleton_of_empty_right {m : Type u_2} {n : Type u_3} {α : Type v} [IsEmpty n] :
            Equations
            • =
            def Matrix.ofAddEquiv {m : Type u_2} {n : Type u_3} {α : Type v} [Add α] :
            (mnα) ≃+ Matrix m n α

            This is Matrix.of bundled as an additive equivalence.

            Equations
            • Matrix.ofAddEquiv = { toEquiv := Matrix.of, map_add' := }
            Instances For
              @[simp]
              theorem Matrix.coe_ofAddEquiv {m : Type u_2} {n : Type u_3} {α : Type v} [Add α] :
              Matrix.ofAddEquiv = Matrix.of
              @[simp]
              theorem Matrix.coe_ofAddEquiv_symm {m : Type u_2} {n : Type u_3} {α : Type v} [Add α] :
              Matrix.ofAddEquiv.symm = Matrix.of.symm
              @[simp]
              theorem Matrix.transpose_transpose {m : Type u_2} {n : Type u_3} {α : Type v} (M : Matrix m n α) :
              M.transpose.transpose = M
              theorem Matrix.transpose_injective {m : Type u_2} {n : Type u_3} {α : Type v} :
              Function.Injective Matrix.transpose
              @[simp]
              theorem Matrix.transpose_inj {m : Type u_2} {n : Type u_3} {α : Type v} {A B : Matrix m n α} :
              A.transpose = B.transpose A = B
              @[simp]
              theorem Matrix.transpose_zero {m : Type u_2} {n : Type u_3} {α : Type v} [Zero α] :
              @[simp]
              theorem Matrix.transpose_eq_zero {m : Type u_2} {n : Type u_3} {α : Type v} [Zero α] {M : Matrix m n α} :
              M.transpose = 0 M = 0
              @[simp]
              theorem Matrix.transpose_add {m : Type u_2} {n : Type u_3} {α : Type v} [Add α] (M N : Matrix m n α) :
              (M + N).transpose = M.transpose + N.transpose
              @[simp]
              theorem Matrix.transpose_sub {m : Type u_2} {n : Type u_3} {α : Type v} [Sub α] (M N : Matrix m n α) :
              (M - N).transpose = M.transpose - N.transpose
              @[simp]
              theorem Matrix.transpose_smul {m : Type u_2} {n : Type u_3} {α : Type v} {R : Type u_10} [SMul R α] (c : R) (M : Matrix m n α) :
              (c M).transpose = c M.transpose
              @[simp]
              theorem Matrix.transpose_neg {m : Type u_2} {n : Type u_3} {α : Type v} [Neg α] (M : Matrix m n α) :
              (-M).transpose = -M.transpose
              theorem Matrix.transpose_map {m : Type u_2} {n : Type u_3} {α : Type v} {β : Type w} {f : αβ} {M : Matrix m n α} :
              M.transpose.map f = (M.map f).transpose
              def Matrix.submatrix {l : Type u_1} {m : Type u_2} {n : Type u_3} {o : Type u_4} {α : Type v} (A : Matrix m n α) (r_reindex : lm) (c_reindex : on) :
              Matrix l o α

              Given maps (r_reindex : l → m) and (c_reindex : o → n) reindexing the rows and columns of a matrix M : Matrix m n α, the matrix M.submatrix r_reindex c_reindex : Matrix l o α is defined by (M.submatrix r_reindex c_reindex) i j = M (r_reindex i) (c_reindex j) for (i,j) : l × o. Note that the total number of row and columns does not have to be preserved.

              Equations
              • A.submatrix r_reindex c_reindex = Matrix.of fun (i : l) (j : o) => A (r_reindex i) (c_reindex j)
              Instances For
                @[simp]
                theorem Matrix.submatrix_apply {l : Type u_1} {m : Type u_2} {n : Type u_3} {o : Type u_4} {α : Type v} (A : Matrix m n α) (r_reindex : lm) (c_reindex : on) (i : l) (j : o) :
                A.submatrix r_reindex c_reindex i j = A (r_reindex i) (c_reindex j)
                @[simp]
                theorem Matrix.submatrix_id_id {m : Type u_2} {n : Type u_3} {α : Type v} (A : Matrix m n α) :
                A.submatrix id id = A
                @[simp]
                theorem Matrix.submatrix_submatrix {l : Type u_1} {m : Type u_2} {n : Type u_3} {o : Type u_4} {α : Type v} {l₂ : Type u_10} {o₂ : Type u_11} (A : Matrix m n α) (r₁ : lm) (c₁ : on) (r₂ : l₂l) (c₂ : o₂o) :
                (A.submatrix r₁ c₁).submatrix r₂ c₂ = A.submatrix (r₁ r₂) (c₁ c₂)
                @[simp]
                theorem Matrix.transpose_submatrix {l : Type u_1} {m : Type u_2} {n : Type u_3} {o : Type u_4} {α : Type v} (A : Matrix m n α) (r_reindex : lm) (c_reindex : on) :
                (A.submatrix r_reindex c_reindex).transpose = A.transpose.submatrix c_reindex r_reindex
                theorem Matrix.submatrix_add {l : Type u_1} {m : Type u_2} {n : Type u_3} {o : Type u_4} {α : Type v} [Add α] (A B : Matrix m n α) :
                (A + B).submatrix = A.submatrix + B.submatrix
                theorem Matrix.submatrix_neg {l : Type u_1} {m : Type u_2} {n : Type u_3} {o : Type u_4} {α : Type v} [Neg α] (A : Matrix m n α) :
                (-A).submatrix = -A.submatrix
                theorem Matrix.submatrix_sub {l : Type u_1} {m : Type u_2} {n : Type u_3} {o : Type u_4} {α : Type v} [Sub α] (A B : Matrix m n α) :
                (A - B).submatrix = A.submatrix - B.submatrix
                @[simp]
                theorem Matrix.submatrix_zero {l : Type u_1} {m : Type u_2} {n : Type u_3} {o : Type u_4} {α : Type v} [Zero α] :
                theorem Matrix.submatrix_smul {l : Type u_1} {m : Type u_2} {n : Type u_3} {o : Type u_4} {α : Type v} {R : Type u_10} [SMul R α] (r : R) (A : Matrix m n α) :
                (r A).submatrix = r A.submatrix
                theorem Matrix.submatrix_map {l : Type u_1} {m : Type u_2} {n : Type u_3} {o : Type u_4} {α : Type v} {β : Type w} (f : αβ) (e₁ : lm) (e₂ : on) (A : Matrix m n α) :
                (A.map f).submatrix e₁ e₂ = (A.submatrix e₁ e₂).map f
                def Matrix.reindex {l : Type u_1} {m : Type u_2} {n : Type u_3} {o : Type u_4} {α : Type v} (eₘ : m l) (eₙ : n o) :
                Matrix m n α Matrix l o α

                The natural map that reindexes a matrix's rows and columns with equivalent types is an equivalence.

                Equations
                • Matrix.reindex eₘ eₙ = { toFun := fun (M : Matrix m n α) => M.submatrix eₘ.symm eₙ.symm, invFun := fun (M : Matrix l o α) => M.submatrix eₘ eₙ, left_inv := , right_inv := }
                Instances For
                  @[simp]
                  theorem Matrix.reindex_apply {l : Type u_1} {m : Type u_2} {n : Type u_3} {o : Type u_4} {α : Type v} (eₘ : m l) (eₙ : n o) (M : Matrix m n α) :
                  (Matrix.reindex eₘ eₙ) M = M.submatrix eₘ.symm eₙ.symm
                  theorem Matrix.reindex_refl_refl {m : Type u_2} {n : Type u_3} {α : Type v} (A : Matrix m n α) :
                  @[simp]
                  theorem Matrix.reindex_symm {l : Type u_1} {m : Type u_2} {n : Type u_3} {o : Type u_4} {α : Type v} (eₘ : m l) (eₙ : n o) :
                  (Matrix.reindex eₘ eₙ).symm = Matrix.reindex eₘ.symm eₙ.symm
                  @[simp]
                  theorem Matrix.reindex_trans {l : Type u_1} {m : Type u_2} {n : Type u_3} {o : Type u_4} {α : Type v} {l₂ : Type u_10} {o₂ : Type u_11} (eₘ : m l) (eₙ : n o) (eₘ₂ : l l₂) (eₙ₂ : o o₂) :
                  (Matrix.reindex eₘ eₙ).trans (Matrix.reindex eₘ₂ eₙ₂) = Matrix.reindex (eₘ.trans eₘ₂) (eₙ.trans eₙ₂)
                  theorem Matrix.transpose_reindex {l : Type u_1} {m : Type u_2} {n : Type u_3} {o : Type u_4} {α : Type v} (eₘ : m l) (eₙ : n o) (M : Matrix m n α) :
                  ((Matrix.reindex eₘ eₙ) M).transpose = (Matrix.reindex eₙ eₘ) M.transpose
                  @[reducible, inline]
                  abbrev Matrix.subLeft {α : Type v} {m l r : } (A : Matrix (Fin m) (Fin (l + r)) α) :
                  Matrix (Fin m) (Fin l) α

                  The left n × l part of an n × (l+r) matrix.

                  Equations
                  Instances For
                    @[reducible, inline]
                    abbrev Matrix.subRight {α : Type v} {m l r : } (A : Matrix (Fin m) (Fin (l + r)) α) :
                    Matrix (Fin m) (Fin r) α

                    The right n × r part of an n × (l+r) matrix.

                    Equations
                    Instances For
                      @[reducible, inline]
                      abbrev Matrix.subUp {α : Type v} {d u n : } (A : Matrix (Fin (u + d)) (Fin n) α) :
                      Matrix (Fin u) (Fin n) α

                      The top u × n part of a (u+d) × n matrix.

                      Equations
                      Instances For
                        @[reducible, inline]
                        abbrev Matrix.subDown {α : Type v} {d u n : } (A : Matrix (Fin (u + d)) (Fin n) α) :
                        Matrix (Fin d) (Fin n) α

                        The bottom d × n part of a (u+d) × n matrix.

                        Equations
                        Instances For
                          @[reducible, inline]
                          abbrev Matrix.subUpRight {α : Type v} {d u l r : } (A : Matrix (Fin (u + d)) (Fin (l + r)) α) :
                          Matrix (Fin u) (Fin r) α

                          The top-right u × r part of a (u+d) × (l+r) matrix.

                          Equations
                          • A.subUpRight = A.subRight.subUp
                          Instances For
                            @[reducible, inline]
                            abbrev Matrix.subDownRight {α : Type v} {d u l r : } (A : Matrix (Fin (u + d)) (Fin (l + r)) α) :
                            Matrix (Fin d) (Fin r) α

                            The bottom-right d × r part of a (u+d) × (l+r) matrix.

                            Equations
                            • A.subDownRight = A.subRight.subDown
                            Instances For
                              @[reducible, inline]
                              abbrev Matrix.subUpLeft {α : Type v} {d u l r : } (A : Matrix (Fin (u + d)) (Fin (l + r)) α) :
                              Matrix (Fin u) (Fin l) α

                              The top-left u × l part of a (u+d) × (l+r) matrix.

                              Equations
                              • A.subUpLeft = A.subLeft.subUp
                              Instances For
                                @[reducible, inline]
                                abbrev Matrix.subDownLeft {α : Type v} {d u l r : } (A : Matrix (Fin (u + d)) (Fin (l + r)) α) :
                                Matrix (Fin d) (Fin l) α

                                The bottom-left d × l part of a (u+d) × (l+r) matrix.

                                Equations
                                • A.subDownLeft = A.subLeft.subDown
                                Instances For