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For u ∉ Q̄ and real algebraic s with s² = uū, the span of 1, u, ū, u³/s³ + u²/s², ū³/s³ + ū²/s² is five-dimensional and contains none of u², ū², 1/(u − b)

Proved
DiazModulus.laurent_cubic_space_excludes_squares_and_reciprocals

by carlok · Oct 14, 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​ and let s∈Q‾s \in \overline{\mathbb{Q}}s∈Q​ be real with s2=uuˉs^2 = u\bar us2=uuˉ (so uˉ=s2/u\bar u = s^2/uuˉ=s2/u; with v=u/sv = u/sv=u/s, conjugation acts as v↦1/vv \mapsto 1/vv↦1/v on coefficients). Put F=u3/s3+u2/s2F = u^3/s^3 + u^2/s^2F=u3/s3+u2/s2 and let W1W_1W1​ be the Q‾\overline{\mathbb{Q}}Q​-span of 1,u,uˉ,F,Fˉ1, u, \bar u, F, \bar F1,u,uˉ,F,Fˉ (in vvv: v−1,1,v,v3+v2,v−3+v−2v^{-1}, 1, v, v^3 + v^2, v^{-3} + v^{-2}v−1,1,v,v3+v2,v−3+v−2). Then the five numbers are free over Q‾\overline{\mathbb{Q}}Q​, and W1W_1W1​ contains none of u2u^2u2, uˉ2\bar u^2uˉ2 and 1/(u−b)1/(u - b)1/(u−b) for non-zero b∈Q‾b \in \overline{\mathbb{Q}}b∈Q​.

Proof. From uˉu=s2\bar u u = s^2uˉu=s2, s3F=u3+su2s^3F = u^3 + su^2s3F=u3+su2 and u3Fˉ=s3+s2uu^3\bar F = s^3 + s^2uu3Fˉ=s3+s2u, the number s3u3ws^3u^3ws3u3w for w=c1+c2u+c3uˉ+c4F+c5Fˉw = c_1 + c_2u + c_3\bar u + c_4F + c_5\bar Fw=c1​+c2​u+c3​uˉ+c4​F+c5​Fˉ is a polynomial of degree 666 in uuu with coefficients c5s6,c5s5,c3s5,c1s3,c2s3,c4s,c4c_5s^6, c_5s^5, c_3s^5, c_1s^3, c_2s^3, c_4s, c_4c5​s6,c5​s5,c3​s5,c1​s3,c2​s3,c4​s,c4​; as uuu is transcendental, every coefficient of a vanishing combination is zero. So the five numbers are free; u2∉W1u^2 \notin W_1u2∈/W1​ because the u5u^5u5 and u6u^6u6 coefficients are tied, and uˉ2=s4/u2∉W1\bar u^2 = s^4/u^2 \notin W_1uˉ2=s4/u2∈/W1​ because the u0u^0u0 and u1u^1u1 coefficients are; for 1/(u−b)1/(u - b)1/(u−b), the cleared identity (X−b)L(X)=s3X3(X - b)L(X) = s^3X^3(X−b)L(X)=s3X3 at X=bX = bX=b gives s3b3=0s^3b^3 = 0s3b3=0.

Novelty. Not found in the sources read; it is short.

Preamble
import Definitions.Def_DiazModulus
Formal statement
open Complex ComplexConjugate

namespace DiazModulus

theorem laurent_cubic_space_excludes_squares_and_reciprocals
    (u s : ℂ) (hu : u ∉ Qbar) (hs : s ∈ Qbar) (hsr : conj s = s) (hss : s * s = u * conj u) :
    LinearIndependent (↥Qbar) ![1, u, conj u, (u ^ 3 / (s * s * s) + u ^ 2 / (s * s)), (conj u ^ 3 / (s * s * s) + conj u ^ 2 / (s * s))] ∧
      u ^ 2 ∉ Submodule.span Qbar ({1, u, conj u, (u ^ 3 / (s * s * s) + u ^ 2 / (s * s)), (conj u ^ 3 / (s * s * s) + conj u ^ 2 / (s * s))} : Set ℂ) ∧
      conj u ^ 2 ∉ Submodule.span Qbar ({1, u, conj u, (u ^ 3 / (s * s * s) + u ^ 2 / (s * s)), (conj u ^ 3 / (s * s * s) + conj u ^ 2 / (s * s))} : Set ℂ) ∧
      ∀ b ∈ Qbar, b ≠ 0 → (u - b)⁻¹ ∉ Submodule.span Qbar ({1, u, conj u, (u ^ 3 / (s * s * s) + u ^ 2 / (s * s)), (conj u ^ 3 / (s * s * s) + conj u ^ 2 / (s * s))} : Set ℂ) := by
  sorry

end DiazModulus
Source
Not found in the sources read. R14 of the Diaz modulus mission. Formal proof: Diaz modulus mission, 14 October 2026 (C. Perassi).

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