Square division in full ring
ProvedD1Bound5.square_division_in_full_ringdiophantine-tuplesnumber-theory
Square divisibility in a full integer ring forces divisibility of the root. This uses integrality in K, not unique factorization in the ring.
Preamble
import Mathlib.Algebra.Polynomial.Monic import Mathlib.Algebra.QuadraticAlgebra.Basic import Mathlib.Algebra.Squarefree.Basic import Mathlib.Data.Int.GCD import Mathlib.LinearAlgebra.Dimension.Free import Mathlib.NumberTheory.NumberField.Norm import Mathlib.Tactic.Linarith import Mathlib.Tactic.LinearCombination import Definitions.Def_D1Bound5_Coordinates_Definitions
Formal statement
section
open scoped NumberField
open Module Polynomial
namespace D1Bound5
variable {K : Type*} [Field K]
variable [NumberField K]
theorem _root_.D1Bound5.square_division_in_full_ring {tau nu : ℤ}
(e : QuadInt tau nu ≃+* 𝓞 K) (a m : ℤ) (ha : a ≠ 0)
{z : QuadInt tau nu} (hz : z*z = ((a*a*m : ℤ) : QuadInt tau nu)) :
∃ y : QuadInt tau nu, (a : QuadInt tau nu)*y = z := by sorry
end D1Bound5
end
Source
D1Bound5/MaximalCoordinates.lean, lines 28-55, SHA-256 db32306018b4cc9c601d0bd15648a6675ec234d51750d3dd04f9988129483527. Project: https://github.com/tomislav-math/d1-bound5-lean