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For u ∉ Q̄ with uū algebraic and G a real polynomial with algebraic coefficients, z = G(Re u, Im u) has no 2×3 configuration in its hull

Proved
DiazModulus.real_polynomial_hull_no_two_by_three_configuration

by carlok · Oct 16, 2026 · Mathlib 0df444a (Lean v4.33.1)

diaz-modulus-leannumber-theorytranscendence

Let u∈C∖Q‾u \in \mathbb{C} \setminus \overline{\mathbb{Q}}u∈C∖Q​ with ρ=uuˉ\rho = u\bar uρ=uuˉ algebraic (so uˉ=ρ/u\bar u = \rho/uuˉ=ρ/u). Let G∈R[a,b]G \in \mathbb{R}[a, b]G∈R[a,b] have algebraic coefficients and z=G(Re u,Im u)z = G(\mathrm{Re}\,u, \mathrm{Im}\,u)z=G(Reu,Imu). Then Q‾+Q‾u+Q‾uˉ+Q‾z+Q‾zˉ\overline{\mathbb{Q}} + \overline{\mathbb{Q}}u + \overline{\mathbb{Q}}\bar u + \overline{\mathbb{Q}}z + \overline{\mathbb{Q}}\bar zQ​+Q​u+Q​uˉ+Q​z+Q​zˉ carries no 2×32 \times 32×3 configuration (free x1,x2x_1, x_2x1​,x2​ and free y1,y2,y3y_1, y_2, y_3y1​,y2​,y3​ over Q‾\overline{\mathbb{Q}}Q​ with all six products xiyjx_iy_jxi​yj​ in the space).

So at a candidate, Roy's theorem cannot exclude such a zzz, for example (Re u)2(\mathrm{Re}\,u)^2(Reu)2 or Re u⋅Im u\mathrm{Re}\,u \cdot \mathrm{Im}\,uReu⋅Imu, from L~\widetilde{\mathcal L}L through its own hull.

Proof. zzz is real, so the span is H0+Q‾zH_0 + \overline{\mathbb{Q}}zH0​+Q​z with H0=Q‾+Q‾u+Q‾uˉH_0 = \overline{\mathbb{Q}} + \overline{\mathbb{Q}}u + \overline{\mathbb{Q}}\bar uH0​=Q​+Q​u+Q​uˉ. Since Re u=(u+uˉ)/2\mathrm{Re}\,u = (u + \bar u)/2Reu=(u+uˉ)/2, Im u=(u−uˉ)/(2i)\mathrm{Im}\,u = (u - \bar u)/(2i)Imu=(u−uˉ)/(2i) and uˉ=ρ/u\bar u = \rho/uuˉ=ρ/u, uNz=R(u)u^Nz = R(u)uNz=R(u) for some R∈Q‾[X]R \in \overline{\mathbb{Q}}[X]R∈Q​[X]. For a real www of this kind outside H0H_0H0​, Theorem B puts www in H0+Q‾tH_0 + \overline{\mathbb{Q}}tH0​+Q​t with t=u2t = u^2t=u2, uˉ2\bar u^2uˉ2 or (u−α)−1(u - \alpha)^{-1}(u−α)−1: if w≡cu2w \equiv cu^2w≡cu2, conjugating gives cu2−cˉuˉ2∈H0cu^2 - \bar c\bar u^2 \in H_0cu2−cˉuˉ2∈H0​, so c=0c = 0c=0 (uuu is transcendental); uˉ2\bar u^2uˉ2 is symmetric; and (u−α)−1(u - \alpha)^{-1}(u−α)−1 is excluded by evaluating at α\alphaα the polynomial identity obtained after multiplying by uN+1(u−α)u^{N+1}(u - \alpha)uN+1(u−α). So no such www carries a configuration. If z∉H0z \notin H_0z∈/H0​ take w=zw = zw=z; if z∈H0z \in H_0z∈H0​, the span is H0⊆H0+Q‾(u2+uˉ2)H_0 \subseteq H_0 + \overline{\mathbb{Q}}(u^2 + \bar u^2)H0​⊆H0​+Q​(u2+uˉ2), and w=u2+uˉ2w = u^2 + \bar u^2w=u2+uˉ2 applies.

Novelty. Not found in the sources read; routine, as a consequence of Theorem B (DiazModulus.circle_point_extension_two_by_three_configuration_iff).

Preamble
import Definitions.Def_DiazModulus
Formal statement
open Complex ComplexConjugate

namespace DiazModulus

theorem real_polynomial_hull_no_two_by_three_configuration {u : ℂ} (hu : u ∉ Qbar)
    (hρ : IsAlgebraic ℚ (u * conj u)) (G : MvPolynomial (Fin 2) ℝ)
    (hG : ∀ s, IsAlgebraic ℚ ((G.coeff s : ℝ) : ℂ)) :
    ¬ ∃ (x : Fin 2 → ℂ) (y : Fin 3 → ℂ), LinearIndependent (↥Qbar) x ∧
      LinearIndependent (↥Qbar) y ∧ ∀ i j, x i * y j ∈
        Submodule.span Qbar ({1, u, conj u, ((MvPolynomial.eval ![u.re, u.im] G : ℝ) : ℂ),
          conj ((MvPolynomial.eval ![u.re, u.im] G : ℝ) : ℂ)} : Set ℂ) := by
  sorry

end DiazModulus
Source
Not found in the sources read. Uses DiazModulus.circle_point_extension_two_by_three_configuration_iff. R16 of the Diaz modulus mission. Formal proof: Diaz modulus mission, 16 October 2026 (C. Perassi).

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