English
In the case p is prime, the quotient by span{hζ.toInteger − 1} is finite.
Русский
Когда p простое, фактор-кольцо по порожденному span{hζ.toInteger − 1} конечное.
LaTeX
$$Finite\\HasQuotient\\\\(\\mathcal{O}_K / \\langle h\\zeta^{\\mathrm{toInteger}} - 1 \\rangle\\\\)$$
Lean4
theorem finite_quotient_span_sub_one' [hcycl : IsCyclotomicExtension { p } ℚ K] (hζ : IsPrimitiveRoot ζ p) :
Finite (𝓞 K ⧸ Ideal.span {hζ.toInteger - 1}) :=
by
have : IsCyclotomicExtension {p ^ (0 + 1)} ℚ K := by simpa using hcycl
replace hζ : IsPrimitiveRoot ζ (p ^ (0 + 1)) := by simpa using hζ
exact hζ.finite_quotient_span_sub_one