English
In an integral closure setting, comap respects prime nesting and going-up properties along towers of rings.
Русский
В рамках интегрального замыкания компарантируемость сохраняется по цепям колец, соблюдая свойства going-up.
LaTeX
$$$$\text{Ideal.IsIntegralClosure.comap}_{}(R,S)\text{ preserves going-up in towers}. $$$$
Lean4
theorem comap_lt_comap {I J : Ideal A} [I.IsPrime] (I_lt_J : I < J) :
I.comap (algebraMap R A) < J.comap (algebraMap R A) :=
let ⟨I_le_J, x, hxJ, hxI⟩ := SetLike.lt_iff_le_and_exists.mp I_lt_J
comap_lt_comap_of_integral_mem_sdiff I_le_J ⟨hxJ, hxI⟩ (IsIntegralClosure.isIntegral R S x)