English
Let f: R → S be a ring hom with integral extension and I an ideal of R such that ker f ≤ I. Then I.map f = ⊤ iff I = ⊤.
Русский
Пусть f: R → S — кольцо-гомоморф, иерархически интегральное расширение, и I — идеал R с ker f ≤ I. Тогда I.map f = ⊤ тогда и только тогда I = ⊤.
LaTeX
$$$I.map f = \top \iff I = \top$$$
Lean4
theorem map_eq_top_iff {R S} [CommRing R] [CommRing S] (f : R →+* S) {I : Ideal R} (hf₁ : Function.Injective f)
(hf₂ : f.IsIntegral) : I.map f = ⊤ ↔ I = ⊤ :=
map_eq_top_iff_of_ker_le f (by simp [(RingHom.injective_iff_ker_eq_bot f).mp hf₁]) hf₂