English
A dual statement to Span equivalence in the span-target setting.
Русский
Семантически двойственный факт для настройки SpanTarget и его конечной версии.
LaTeX
$$$\\forall P,\\; \\RingHom.OfLocalizationSpanTarget P \\;\\Leftrightarrow \\RingHom.OfLocalizationFiniteSpanTarget P$$$
Lean4
theorem of_bijective (H : RingHom.HoldsForLocalizationAway P) (hf : Function.Bijective f) : P f :=
by
letI := f.toAlgebra
have := IsLocalization.at_units (.powers (1 : R)) (by simp)
have := IsLocalization.isLocalization_of_algEquiv (.powers (1 : R)) (AlgEquiv.ofBijective (Algebra.ofId R S) hf)
exact H _ 1