English
Under standard hypotheses, each entry of the matrix representing the change of basis is integral.
Русский
При обычных предположениях каждый элемент матрицы перехода баз задаёт интегральный коэффициент.
LaTeX
$$$\\forall i\\in Fin\\; B:\\, \\forall j\\in Fin\\; IsIntegral R (B.basis.toMatrix B'.basis i j)$$$
Lean4
protected theorem nontrivial [IsDomain R] (h : degree f ≠ 0) : Nontrivial (AdjoinRoot f) :=
Ideal.Quotient.nontrivial
(by
simp_rw [Ne, span_singleton_eq_top, Polynomial.isUnit_iff, not_exists, not_and]
rintro x hx rfl
exact h (degree_C hx.ne_zero))