Lemmas for ideal in polynomial span by monic polynomial #
theorem
Polynomial.exists_monic_span
{k : Type u_2}
[Field k]
(I : Ideal (Polynomial k))
(ne : I ≠ ⊥)
:
∃ (f : Polynomial k), f.Monic ∧ I = Ideal.span {f}
theorem
Polynomial.exists_monic_span_sup_map_eq
(R : Type u_1)
[CommRing R]
(p : Ideal (Polynomial R))
(ism : (Ideal.comap C p).IsMaximal)
(ne : p ≠ Ideal.map C (Ideal.comap C p))
:
∃ (f : Polynomial R), f.Monic ∧ p = Ideal.map C (Ideal.comap C p) ⊔ Ideal.span {f}