English
Similarly, an endomorphism f on M commutes with the identity map: f ∘ id = id ∘ f.
Русский
Аналогично, эндоморфизм f на M коммутирует с тождественным отображением: f ∘ id = id ∘ f.
LaTeX
$$Commute\(f, LinearMap.id\)$$
Lean4
/-- Let `M` be an `(m × n)`-matrix over `R`.
Then `Matrix.toMvPolynomial M` is the family (indexed by `i : m`)
of multivariate polynomials in `n` variables over `R` that evaluates on `c : n → R`
to the dot product of the `i`-th row of `M` with `c`:
`Matrix.toMvPolynomial M i` is the sum of the monomials `C (M i j) * X j`. -/
noncomputable def toMvPolynomial (M : Matrix m n R) (i : m) : MvPolynomial n R :=
∑ j, monomial (.single j 1) (M i j)