English
If I is primary, then its minimal primes are exactly the radical of I.
Русский
Если I — первичный идеал, то его минимальные primes равны единственному элементу {√I}.
LaTeX
$$$I\text{ is primary }\Rightarrow I.minimalPrimes = \{ I.radical \}$$$
Lean4
theorem minimalPrimes_eq_subsingleton (hI : I.IsPrimary) : I.minimalPrimes = { I.radical } :=
by
ext J
constructor
·
exact fun H =>
let e := H.1.1.radical_le_iff.mpr H.1.2
(H.2 ⟨Ideal.isPrime_radical hI, Ideal.le_radical⟩ e).antisymm e
· rintro (rfl : J = I.radical)
exact ⟨⟨Ideal.isPrime_radical hI, Ideal.le_radical⟩, fun _ H _ => H.1.radical_le_iff.mpr H.2⟩