English
There is a canonical element pairing s with (r, n) describing how s relates to powers of x.
Русский
Существует каноническая парация, сопоставляющая s пары (r, n), описывающая отношение s к степеням x.
LaTeX
$$sec (s) : R × Nat$$
Lean4
/-- For `s : S` with `S` being the localization of `R` away from `x`,
this is a choice of `(r, n) : R × ℕ` such that `s * algebraMap R S (x ^ n) = algebraMap R S r`. -/
noncomputable def sec (s : S) : R × ℕ :=
⟨(IsLocalization.sec (Submonoid.powers x) s).1, (IsLocalization.sec (Submonoid.powers x) s).2.property.choose⟩