English
For any x, the evaluated polyCharpolyAux at x equals the characteristic polynomial of φ x.
Русский
При подстановке x характеристический полином φ x равен результату сопоставления polyCharpolyAux.
LaTeX
$$(polyCharpolyAux φ b b_m).map (MvPolynomial.eval (b.repr x)) = (φ x).charpoly$$
Lean4
theorem polyCharpolyAux_map_eq_toMatrix_charpoly (x : L) :
(polyCharpolyAux φ b bₘ).map (MvPolynomial.eval (b.repr x)) = (toMatrix bₘ bₘ (φ x)).charpoly :=
by
rw [polyCharpolyAux, Polynomial.map_map, ← MvPolynomial.eval₂Hom_C_eq_bind₁, MvPolynomial.comp_eval₂Hom,
charpoly.univ_map_eval₂Hom]
congr
ext
rw [of_apply, Function.curry_apply, toMvPolynomial_eval_eq_apply, LinearEquiv.symm_apply_apply]
rfl