English
If A → B is a prime localization and modules are flat, then the localized AtPrime rings preserve flatness.
Русский
Если A → B локализуется поprime и модули плоски, то локализация AtPrime сохраняет плоскость.
LaTeX
$$$\\text{Flat}(\\mathrm{Localization.AtPrime} p, \\mathrm{Localization.AtPrime} P)$$$
Lean4
instance [Module.Flat A B] (p : Ideal A) [p.IsPrime] (P : Ideal B) [P.IsPrime] [P.LiesOver p] :
Module.Flat (Localization.AtPrime p) (Localization.AtPrime P) :=
by
rw [Module.flat_iff_of_isLocalization (Localization.AtPrime p) p.primeCompl]
exact Module.Flat.trans A B (Localization.AtPrime P)