Uniform Littlewood conjecture

Let (α,β)(\alpha,\beta) be a pair of real numbers, and let ϵ>0\epsilon>0. Consider the system

{p+qαr+qβ<ϵ/TqT.\begin{cases} |p+q\alpha||r+q\beta|<\epsilon/T\\ q\leq T. \end{cases}

A pair is called multiplicatively singular if, for every ϵ>0\epsilon>0, this system has a nonzero integer solution for every sufficiently large TT. Uniform Littlewood conjecture. Every pair (α,β)(\alpha,\beta) is multiplicatively singular; equivalently, for every pair and every ϵ>0\epsilon>0, the system has solutions (p,r,q)Z×Z×N(p,r,q)\in\mathbb{Z}\times\mathbb{Z}\times\mathbb{N} for all sufficiently large positive TT. The surrounding text states that this question is wide open, although multiplicatively singular pairs have full Lebesgue measure.

Equivalent formulations 1

Other statements of this same problem, merged from separate entries. Each is equivalent to the statement above — proving any one settles them all.

  1. The uniform Littlewood conjecture

    Let xixi and ζ\zeta be real numbers. The uniform Littlewood conjecture asserts that

    limQQminqZ,0<qQqξqζ=0.\lim_{Q\to\infty} Q \min_{q\in\mathbb{Z},\,0<q\leq Q} \Vert q\xi\Vert\cdot\Vert q\zeta\Vert=0.

    Uniform Littlewood conjecture. For any real numbers xi,ζxi,\zeta,

    limQQminqZ,0<qQqξqζ=0.\lim_{Q\to\infty} Q \min_{q\in\mathbb{Z},\,0<q\leq Q} \Vert q\xi\Vert\cdot\Vert q\zeta\Vert=0.

    The paper states that this conjecture is false and provides counterexamples forming a residual set; consequently, the conjecture is refuted.

    source: Johannes Schleischitz, “Disproof of the uniform Littlewood conjecture”, arXiv:2603.12611 (2026).

Sources & referencesView supporting material

Primary source

Dmitry Kleinbock and Chengyang Wu, “Simultaneously bounded and dense orbits for commuting Cartan actions”, arXiv:2509.05272 (2025).

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