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
ProvedDiazModulus.real_polynomial_hull_no_two_by_three_configurationLet with algebraic (so ). Let have algebraic coefficients and . Then carries no configuration (free and free over with all six products in the space).
So at a candidate, Roy's theorem cannot exclude such a , for example or , from through its own hull.
Proof. is real, so the span is with . Since , and , for some . For a real of this kind outside , Theorem B puts in with , or : if , conjugating gives , so ( is transcendental); is symmetric; and is excluded by evaluating at the polynomial identity obtained after multiplying by . So no such carries a configuration. If take ; if , the span is , and applies.
Novelty. Not found in the sources read; routine, as a consequence of Theorem B (DiazModulus.circle_point_extension_two_by_three_configuration_iff).
import Definitions.Def_DiazModulus
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