English
Under appropriate towers and integrality conditions, a strict inequality of ideals transfers along comaps in the integral closure context.
Русский
При заданных условиях интегралного замыкания и тензорных степеней цепей неравенство между эзалями сохраняется через образ обратного образа.
LaTeX
$$$$\text{IsPrime}(I)\Rightarrow I^{\mathrm{comap}} < J^{\mathrm{comap}} \text{ whenever } I < J.$$$
Lean4
theorem isMaximal_of_isMaximal_comap (I : Ideal A) [I.IsPrime] (hI : IsMaximal (I.comap (algebraMap R A))) :
IsMaximal I :=
have : Algebra.IsIntegral R A := IsIntegralClosure.isIntegral_algebra R S
isMaximal_of_isIntegral_of_isMaximal_comap I hI