The square-norm integers are covered by their integer-translation fibers. Fibers with even generated-subfield index are absorbed into the small-subfield set when there is no index-two intermediate field.
theorem
CCDN.exists_norm_curve_exception_split
(K : Type u_1)
[Field K]
[NumberField K]
(hnoTwo : ∀ (L : IntermediateField ℚ K), Module.finrank (↥L) K ≠ 2)
(B : ℝ)
:
∃ (β : ↥(boundedSquareNormTranslationClasses K B) → NumberField.RingOfIntegers K),
Function.Injective β ∧ (∀ (q : ↥(boundedSquareNormTranslationClasses K B)) (w : NumberField.InfinitePlace K), w ↑(β q) ≤ B) ∧ (boundedSquareNormIntegers K B).ncard ≤ (boundedSmallSubfieldIntegers K B).ncard + ∑ q : ↥(boundedSquareNormTranslationClasses K B),
if Odd (Module.finrank (↥ℚ⟮↑(β q)⟯) K) then
count (signedNormCurveLocus K (β q) 1) (max (2 * B) √(B ^ Module.finrank ℚ K)) + count (signedNormCurveLocus K (β q) (-1)) (max (2 * B) √(B ^ Module.finrank ℚ K))
else 0
For a number field K without an intermediate field of index two, there is an injective family
of algebraic integers β q bounded by B, indexed by the bounded square-norm translation
classes, such that the number of bounded square-norm integers is at most the number of bounded
integers in small subfields plus the number of points of height at most
max (2 * B) (√(B ^ n)) on the signed norm curves for those β q with [K : ℚ(β q)] odd.