English
Finite presentation can be checked on a standard covering of the target as in the SpanTarget criterion.
Русский
Конечное презентование можно проверить по стандартному покрытию цели как в критерии SpanTarget.
LaTeX
$$$\text{OfLocalizationSpanTarget }\operatorname{FiniteType}$$$
Lean4
theorem finiteType_ofLocalizationSpanTarget : OfLocalizationSpanTarget @FiniteType :=
by
introv R hs H
algebraize [f]
replace H : ∀ r ∈ s, Algebra.FiniteType R (Localization.Away (r : S)) :=
by
intro r hr; simp_rw [RingHom.FiniteType] at H; convert H ⟨r, hr⟩; ext
simp_rw [Algebra.smul_def]; rfl
exact Algebra.FiniteType.of_span_eq_top_target s hs H