Lemmas on idempotent finitely generated ideals #
theorem
Ideal.isIdempotentElem_iff_of_fg
{R : Type u_1}
[CommRing R]
(I : Ideal R)
(h : I.FG)
:
IsIdempotentElem I ↔ ∃ (e : R), IsIdempotentElem e ∧ I = R ∙ e
A finitely generated idempotent ideal is generated by an idempotent element
theorem
Ideal.isIdempotentElem_iff_eq_bot_or_top
{R : Type u_1}
[CommRing R]
[IsDomain R]
(I : Ideal R)
(h : I.FG)
:
IsIdempotentElem I ↔ I = ⊥ ∨ I = ⊤