English
The set-theoretic expression of vanishingIdeal via SetLike equality: the coe of vanishingIdeal t equals the predicate defining all f that vanish on t.
Русский
Пусть выражение vanishingIdeal через множество; равенство по присвоению: множество f, которые исчезают на t.
LaTeX
$$$\\\\forall t \\\\in \\Set(PrimeSpectrum(R)), \\\\operatorname{coe}(\\\\operatorname{vanishingIdeal}(t)) = \\{ f \\\\mid \\\\forall x \\\\in t, f \\\\in x.asIdeal \}$$$
Lean4
theorem coe_vanishingIdeal (t : Set (PrimeSpectrum R)) :
(vanishingIdeal t : Set R) = {f : R | ∀ x ∈ t, f ∈ x.asIdeal} :=
by
ext f
rw [vanishingIdeal, SetLike.mem_coe, Submodule.mem_iInf]
apply forall_congr'; intro x
rw [Submodule.mem_iInf]