English
Membership in the canonicalEquiv image equals the existence of a representative from the original ideal after localization.
Русский
Принадлежность к образу canonicalEquiv равна существованию представителя из исходного идеала после локализации.
LaTeX
$$$ x \\in canonicalEquiv S P P' I \\iff \\exists y \\in I, \\ IsLocalization.map P' (RingHom.id R) (y) = x $$$
Lean4
@[simp]
theorem mem_canonicalEquiv_apply {I : FractionalIdeal S P} {x : P'} :
x ∈ canonicalEquiv S P P' I ↔
∃ y ∈ I,
IsLocalization.map P' (RingHom.id R) (fun y (hy : y ∈ S) => show RingHom.id R y ∈ S from hy) (y : P) = x :=
by
rw [canonicalEquiv, mapEquiv_apply, mem_map]
exact ⟨fun ⟨y, mem, Eq⟩ => ⟨y, mem, Eq⟩, fun ⟨y, mem, Eq⟩ => ⟨y, mem, Eq⟩⟩