English
There is a linear equivalence between matrices and linear maps given by right multiplication.
Русский
Существует линейное эквивалентное соответствие между матрицами и линейными отображениями, задаваемое правым умножением.
LaTeX
$$toMatrixRight' : Matrix m n R ≃ₗ[Rᵐᵒᵖ] (m → R) →ₗ[R] n → R$$
Lean4
/-- If `M` and `M'` are each other's inverse matrices, they provide an equivalence between `n → A`
and `m → A` corresponding to `M.vecMul` and `M'.vecMul`. -/
@[simps]
def toLinearEquivRight'OfInv [Fintype n] [DecidableEq n] {M : Matrix m n R} {M' : Matrix n m R} (hMM' : M * M' = 1)
(hM'M : M' * M = 1) : (n → R) ≃ₗ[R] m → R :=
{ LinearMap.toMatrixRight'.symm M' with
toFun := Matrix.toLinearMapRight' M'
invFun := Matrix.toLinearMapRight' M
left_inv := fun x ↦ by rw [← Matrix.toLinearMapRight'_mul_apply, hM'M, Matrix.toLinearMapRight'_one, id_apply]
right_inv := fun x ↦ by rw [← Matrix.toLinearMapRight'_mul_apply, hMM', Matrix.toLinearMapRight'_one, id_apply] }