English
Under the admissibility hypothesis, the class group of S is finite when S is an integral closure in an algebraic setting.
Русский
При допущении допустимости существование конечной группы классов для S как интегральной замкнутости при алгебраической обстановке.
LaTeX
$$$ \\text{Fintype } (\\mathrm{ClassGroup}(S)) $ under admissibility and algebraicity$$
Lean4
theorem mkMMem_surjective [IsDedekindDomain S] [Algebra.IsAlgebraic R S] :
Function.Surjective (ClassGroup.mkMMem bS adm) := by
intro I'
obtain ⟨⟨I, hI⟩, rfl⟩ := ClassGroup.mk0_surjective I'
obtain ⟨J, mk0_eq_mk0, J_dvd⟩ := exists_mk0_eq_mk0 bS adm ⟨I, hI⟩
exact ⟨⟨J, J_dvd⟩, mk0_eq_mk0.symm⟩