arXiv:2607.27780v1
Abstract
In a blogpost in 2009, Gowers raised a possible approach to Littlewood's conjecture in Diophantine approximation, leading to a question about the existence of sufficiently many points in the unit cube such that "hyperbolic distance" between any two of them is large. In this note we answer this question by an explicit construction. This shows that this approach to prove Littlewood's conjecture cannot work, unless some further refinements are added.
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Detailed mathematical audit
01Statements3 reported findingsCorrect
The central lattice theorem, its finite-point consequence, and the Delsarte bounds are correct. The exact- conclusion follows immediately from the lattice-point asymptotic by taking a subset and absorbing finitely many small cases, so the mandatory finding gate records no gap there.
Existence of a product-admissible full-rank lattice
Pages 1–2 · Theorem 2 · arXiv:2607.27780v1
For a totally real number field of degree , the Minkowski image of is a full-rank lattice in . For every nonzero , the coordinate product is , a nonzero integer, and is therefore at least . Hence the lattice meets only at the origin.
Affirmative answer to Gowers's finite-point question
Page 2 · Paragraph following Remark 3 · arXiv:2607.27780v1
The number of lattice points in the growing cube is asymptotic to , while distinct scaled points have coordinate-product separation at least . For any fixed , selecting points once the count exceeds , and decreasing to cover the finitely many smaller values of , gives the claimed separation for every positive integer .
Delsarte quantities and asymptotic bounds
Pages 3–4 · Section 3 · arXiv:2607.27780v1
The autocorrelation measure of a separated point set has the stated support, atom, mass, and nonnegative Fourier coefficients. The test function is positive definite, is nonpositive outside because it vanishes there, and has integral . These facts, together with the applicable strong-duality theorem, give the displayed bounds and .
Strong duality source, Theorem 5.6 ↗02Proofs4 reported findingsCorrect
All substantive proof steps and material cited inputs are correct and complete after immediate-consequence closure. Three literal notation defects have unique, verified repairs and remain visible in yellow without lowering the proof status.
An extra closing parenthesis should be removed
Page 1 · Paragraph immediately after the display defining · arXiv:2607.27780v1
The factor is printed as . Remove the extra closing parenthesis to obtain . The correction is uniquely mechanical and changes no inequality or argument.
The cyclotomic subgroup generator has the wrong exponent
Page 2 · Footnote 1 to the proof of Theorem 2 · arXiv:2607.27780v1
The printed automorphism need not generate a subgroup of order ; for and , exponent generates the whole Galois group. If is a primitive root modulo , replace the subgroup by , equivalently the unique subgroup of order . Its fixed field has degree , and it is totally real because is even, so contains complex conjugation. The required subgroup order and index uniquely determine this verified mechanical repair; the norm proof is unchanged.
The strict inequality should be non-strict
Page 2 · Display immediately after the asymptotic for · arXiv:2607.27780v1
The display prints . Replace by . Theorem 2 gives , with equality possible, and this non-strict bound is exactly what the application requires.
Convolution and strong-duality argument
Pages 3–4 · Section 3 · arXiv:2607.27780v1
The Fourier-positivity, support, normalization, and mass calculations are correct with the stated Haar normalization. The cited strong-duality result applies to this compact Abelian-group setting, and the paper also gives a valid direct proof of the upper bound .
Strong duality source, Theorem 5.6 and Remark 5.4 ↗03Novelty1 reported findingContains non-new main statements
The central admissible-lattice theorem and the resulting finite-point construction follow directly from a publicly available 2018 Frolov-lattice construction.
The admissible lattice and resulting point construction were already available
Theorem 2 on pages 1–2 and its consequence for Problem 1 on page 2 · arXiv:2607.27780v1
Kacwin, Oettershagen, Mario Ullrich, and Tino Ullrich, public on February 23, 2018, define an admissible lattice by . Their Proposition 2.2 and Equations (1.5)–(1.6) construct, in every dimension, a Vandermonde lattice with minimum product . Thus every nonzero satisfies , exactly the condition in Theorem 2. Their scaling and lattice-point formulas, Equations (1.3)–(1.4), then immediately yield point sets in the unit cube with cardinality proportional to the scale and product separation proportional to its reciprocal; selecting exactly points gives the stated answer to Gowers's question.
Kacwin–Oettershagen–Ullrich–Ullrich, Definition 2.1 and Proposition 2.2 ↗