Komlós conjecture

DefinitionSigns indexed by two elements#✓fully proved

For \(s \in \{0, 1\}\), the associated real sign is \(-1\) if \(s = 0\) and \(1\) if \(s = 1\).

def signValue (s : Fin 2) : ℝ := if s = 0 then -1 else 1
Used by 2

DefinitionDiscrepancy of a real matrix#✓fully proved

For a real \(m \times n\) matrix \(A\), the discrepancy of \(A\) is the infimum, over all sign vectors \(x \in \{-1, 1\}^n\), of the maximum norm \(\|Ax\|_\infty = \max_i |(Ax)_i|\) (which is \(0\) when \(m = 0\)), taken in \([0, \infty]\).

def discrepancy (A : Matrix (Fin m) (Fin n) ℝ) : ENNReal :=
  ⨅ x : Fin n → Fin 2, ENNReal.ofReal ‖A.mulVec (fun j => signValue (x j))‖
Uses 1 · Used by 2

DefinitionMatrices with columns in the unit ball#✓fully proved

A real \(m \times n\) matrix \(A\) is column admissible when every column of \(A\) lies in the closed Euclidean unit ball, that is, \(\sum_{i=1}^{m} A_{ij}^2 \le 1\) for every column index \(j\).

def ColumnAdmissible (A : Matrix (Fin m) (Fin n) ℝ) : Prop :=
  ∀ j, ∑ i, (A i j) ^ 2 ≤ 1
Used by 3

DefinitionKomlós constant in a fixed dimension#✓fully proved

For a natural number \(n\), this is the supremum of the discrepancy of \(A\) over all real \(n \times n\) matrices \(A\) whose columns all have Euclidean norm at most \(1\), taken in \([0, \infty]\). The definition also applies to \(n = 0\).

def dimensionConstant (n : ℕ) : ENNReal :=
  ⨆ A : {A : Matrix (Fin n) (Fin n) ℝ // ColumnAdmissible A}, discrepancy A.1
Uses 2 · Used by 8

DefinitionKomlós constant#✓fully proved

The Komlós constant is the supremum, over all integers \(n \ge 1\), of the Komlós constant in dimension \(n\), namely the supremum of the discrepancy of \(A\) over all real \(n \times n\) matrices \(A\) whose columns all have Euclidean norm at most \(1\). It is taken in \([0, \infty]\).

def komlosConstant : ENNReal :=
  ⨆ n : {n : ℕ // 1 ≤ n}, dimensionConstant n.1
Uses 1 · Used by 2

TheoremThe discrepancy is attained#✓fully proved

For every real \(m \times n\) matrix \(A\), including the cases \(m = 0\) and \(n = 0\), there is a sign vector \(x \in \{-1, 1\}^n\) such that the discrepancy of \(A\) equals \(\|Ax\|_\infty\).

theorem discrepancy_attained (A : Matrix (Fin m) (Fin n) ℝ) :
    ∃ x : Fin n → Fin 2,
      discrepancy A = ENNReal.ofReal ‖A.mulVec (fun j => signValue (x j))‖
Uses 2

DefinitionUniform discrepancy bound for vectors in the unit ball#✓fully proved

The statement that there is a real constant \(C > 0\) such that for all natural numbers \(n\) and \(d\) and all vectors \(v_1, \dots, v_n \in \mathbb{R}^d\) of Euclidean norm at most \(1\), writing \(v_{ij}\) for the \(j\)-th coordinate of \(v_i\), there are signs \(\varepsilon_1, \dots, \varepsilon_n \in \{-1, 1\}\) with \(\left|\sum_{i=1}^{n} \varepsilon_i v_{ij}\right| \le C\) for every coordinate index \(j\).

def UniformRectangularBound : Prop :=
  ∃ C : ℝ, 0 < C ∧
    ∀ (n d : ℕ) (v : Fin n → Fin d → ℝ),
      (∀ i, ∑ j, (v i j) ^ 2 ≤ 1) →
        ∃ epsilon : Fin n → ℝ,
          (∀ i, epsilon i = 1 ∨ epsilon i = -1) ∧
          ∀ j, |∑ i, epsilon i * v i j| ≤ C
Used by 1

DefinitionEquivalence of the square and rectangular Komlós formulations (statement)#✓fully proved

The statement that the uniform discrepancy bound for vectors in the unit ball holds if and only if the Komlós constant is finite.

def constantFormulationEquivalence : Prop :=
  UniformRectangularBound ↔ komlosConstant < ⊤
Sources
  • optimization catalogue C24a, line 26, and AIM Problem 1.05. The padding bridge is requested, not assumed or claimed definitional.
Uses 2 · Used by 1

DefinitionBeck–Spencer–Gluskin logarithmic upper bound (statement)#✓fully proved

The statement that there are a real number \(c > 0\) and a natural number \(N \ge 3\) such that for every natural number \(n \ge N\), the Komlós constant in dimension \(n\) is at most \(c \log n\), where \(\log\) is the natural logarithm.

def beckSpencerGluskinLogUpperBound : Prop :=
  ∃ c : ℝ, 0 < c ∧ ∃ N : ℕ, 3 ≤ N ∧ ∀ n : ℕ, N ≤ n →
    dimensionConstant n ≤ ENNReal.ofReal (c * Real.log n)
Sources
  • optimization catalogue C24a, line 35, Beck (1981), Spencer (1985), and Gluskin (1989); their full original theorem texts remain a primary-source gap.
Uses 1 · Used by 1

DefinitionStatement of Banaszczyk's Komlós bound#✓fully proved

The proposition that there are a real constant \(c > 0\) and a natural number \(N \ge 3\) such that for every natural number \(n \ge N\), the Komlós constant in dimension \(n\) is at most \(c \sqrt{\log n}\), where \(\log\) is the natural logarithm.

def banaszczyk1998SqrtLogUpperBound : Prop :=
  ∃ c : ℝ, 0 < c ∧ ∃ N : ℕ, 3 ≤ N ∧ ∀ n : ℕ, N ≤ n →
    dimensionConstant n ≤ ENNReal.ofReal (c * Real.sqrt (Real.log n))
Sources
  • optimization catalogue C24a, line 36, Banaszczyk (1998), also reported in retained BJ2025 introduction and BDG2019 Theorem komlos.
Uses 1 · Used by 1

DefinitionStatement of the sublogarithmic Komlós bound#✓fully proved

The proposition that for every real \(\varepsilon > 0\) there is a natural number \(N \ge 3\) such that for every natural number \(n \ge N\), the Komlós constant in dimension \(n\) is at most \(\varepsilon \log n\), where \(\log\) is the natural logarithm. In other words, the Komlós constant in dimension \(n\) is \(o(\log n)\).

def banaszczykSublogUpperBound : Prop :=
  ∀ ε : ℝ, 0 < ε → ∃ N : ℕ, 3 ≤ N ∧ ∀ n : ℕ, N ≤ n →
    dimensionConstant n ≤ ENNReal.ofReal (ε * Real.log n)
Sources
  • optimization catalogue C24a, line 36, the o(log n) comment.
Uses 1 · Used by 1

DefinitionStatement of the Bansal–Dadush–Garg Komlós bound#✓fully proved

The proposition that there are a real constant \(c > 0\) and a natural number \(N \ge 3\) such that for every natural number \(n \ge N\), the Komlós constant in dimension \(n\) is at most \(c \sqrt{\log n}\), where \(\log\) is the natural logarithm.

Only this numerical bound is stated, not the polynomial-time algorithm of the source.

def bdg2019NumericalSqrtLogUpperBound : Prop :=
  ∃ c : ℝ, 0 < c ∧ ∃ N : ℕ, 3 ≤ N ∧ ∀ n : ℕ, N ≤ n →
    dimensionConstant n ≤ ENNReal.ofReal (c * Real.sqrt (Real.log n))
Sources
  • Bansal, Dadush, and Garg, arXiv1605.02882, retained introduction lines 52-60, Theorem komlos; efficient randomized/high-probability computation is an explicit separate gap.
Uses 1 · Used by 1

DefinitionStatement of the Bansal–Jiang Komlós bound#✓fully proved

The proposition that there are a real constant \(c > 0\), a natural number \(p\) and a natural number \(N \ge 3\) such that for every natural number \(n \ge N\), the Komlós constant in dimension \(n\) is at most \(c (\log n)^{1/4} (\log \log n)^p\), where \(\log\) is the natural logarithm.

def bansalJiang2025QuarterLogUpperBound : Prop :=
  ∃ c : ℝ, 0 < c ∧ ∃ p : ℕ, ∃ N : ℕ, 3 ≤ N ∧ ∀ n : ℕ, N ≤ n →
    dimensionConstant n ≤ ENNReal.ofReal
      (c * (Real.log n) ^ (1 / 4 : ℝ) * (Real.log (Real.log n)) ^ p)
Sources
  • Bansal and Haotian Jiang, arXiv2508.03961, retained abstract lines 1-9 and introduction Theorem thm:Komlos. The abstract explicitly defines tilde as poly(log log n); no degree is invented.
Uses 1 · Used by 1

DefinitionStatement of the little-o square-root-log Komlós bound#✓fully proved

The proposition that for every real \(\varepsilon > 0\) there is a natural number \(N \ge 3\) such that for every natural number \(n \ge N\), the Komlós constant in dimension \(n\) is at most \(\varepsilon \sqrt{\log n}\), where \(\log\) is the natural logarithm. In other words, the Komlós constant in dimension \(n\) is \(o(\sqrt{\log n})\).

def bansalJiang2025LittleSqrtLogUpperBound : Prop :=
  ∀ ε : ℝ, 0 < ε → ∃ N : ℕ, 3 ≤ N ∧ ∀ n : ℕ, N ≤ n →
    dimensionConstant n ≤ ENNReal.ofReal (ε * Real.sqrt (Real.log n))
Sources
  • optimization catalogue C24a, line 38, and BJ2025's retained abstract.
Uses 1 · Used by 1

DefinitionKunisky's lower bound for the Komlós constant (statement)#✓fully proved

The statement that the Komlós constant is at least \(1 + \sqrt{2}\).

The bound concerns the supremum over all dimensions; it does not assert that any single dimension attains \(1 + \sqrt{2}\).

def kunisky2023LowerBound : Prop :=
  ENNReal.ofReal (1 + Real.sqrt 2) ≤ komlosConstant
Sources
  • optimization catalogue C24a, line 45, and retained Kunisky arXiv2111.02974v1, Theorem 1.1.
Uses 1 · Used by 1

DefinitionInfinitely many dimensions with Komlós constant at least \(1 + \sqrt{2}\) (statement)#✓fully proved

The statement that there are infinitely many natural numbers \(n \ge 1\) such that the Komlós constant in dimension \(n\) is at least \(1 + \sqrt{2}\).

def kuniskyInfinitelyManyDimensionsLowerBound : Prop :=
  {n : ℕ | 1 ≤ n ∧ ENNReal.ofReal (1 + Real.sqrt 2) ≤ dimensionConstant n}.Infinite
Sources
  • optimization catalogue C24a, line 53. Retained Kunisky v1 only gives a sequence approaching the endpoint from below; the journal2023 comparison is unresolved. This request does not certify exact finite attainment.
Uses 1 · Used by 1

DefinitionKomlós conjecture for vector colorings (statement)#✓fully proved

The statement that for all natural numbers \(m\) and \(n \ge 1\) and every real \(m \times n\) matrix \(A\) whose columns all lie in the closed Euclidean unit ball, there are unit vectors \(u_1, \dots, u_n\) in the Euclidean space \(\mathbb{R}^n\) such that \(\lVert \sum_{j=1}^{n} A_{ij} u_j \rVert \le 1\) for every row index \(i\), where \(\lVert \cdot \rVert\) is the Euclidean norm.

def nikolov2013VectorColoringBound : Prop :=
  ∀ (m n : ℕ), 1 ≤ n → ∀ A : Matrix (Fin m) (Fin n) ℝ, ColumnAdmissible A →
    ∃ u : Fin n → EuclideanSpace ℝ (Fin n), (∀ j, ‖u j‖ = 1) ∧
      ∀ i, ‖∑ j, A i j • u j‖ ≤ 1
Sources
  • Nikolov, arXiv1301.4039, retained KomlosSDP.tex lines 115-139, Theorem thm:main. Positive column dimension is explicit.
Uses 1 · Used by 1

DefinitionStatement of Nikolov's bound on vector discrepancy#✓fully proved

This is the proposition that for all natural numbers \(m\) and \(n\) with \(n \ge 1\) and every real \(m \times n\) matrix \(A\) whose columns all lie in the closed Euclidean unit ball, that is, \(\sum_{i} A_{ij}^2 \le 1\) for every column \(j\), the vector discrepancy of \(A\) is at most \(1\).

This bounds the unit-vector relaxation, not the discrepancy over sign vectors.

def nikolov2013VectorDiscrepancyUpperBound : Prop :=
  ∀ (m n : ℕ), 1 ≤ n → ∀ A : Matrix (Fin m) (Fin n) ℝ, ColumnAdmissible A →
    vectorDiscrepancy A ≤ 1
Sources
  • Nikolov, arXiv1301.4039, retained KomlosSDP.tex, Theorem thm:main, and optimization catalogue C24a, line 55.
Uses 2 · Used by 1

TheoremThe square and rectangular Komlós formulations are equivalent#●ready to prove

The following two conditions are equivalent. (a) There is a real constant \(C > 0\) such that for all natural numbers \(n\) and \(d\) and all vectors \(v_1, \dots, v_n \in \mathbb{R}^d\) of Euclidean norm at most \(1\), writing \(v_{ij}\) for the \(j\)-th coordinate of \(v_i\), there are signs \(\varepsilon_1, \dots, \varepsilon_n \in \{-1, 1\}\) with \(\left|\sum_{i=1}^{n} \varepsilon_i v_{ij}\right| \le C\) for every coordinate index \(j\). (b) The Komlós constant, the supremum over all \(n \ge 1\) of the discrepancy of real \(n \times n\) matrices whose columns all have Euclidean norm at most \(1\), is finite.

theorem_wanted constantFormulationEquivalence_holds : constantFormulationEquivalence
Sources
  • optimization catalogue C24a, line 26, and AIM Problem 1.05.
Uses 1

TheoremBeck–Spencer–Gluskin logarithmic upper bound for the Komlós constant#●ready to prove

There are a real number \(c > 0\) and a natural number \(N \ge 3\) such that for every natural number \(n \ge N\), the Komlós constant in dimension \(n\) (the supremum of the discrepancy of real \(n \times n\) matrices whose columns all have Euclidean norm at most \(1\), taken in \([0, \infty]\)) is at most \(c \log n\), where \(\log\) is the natural logarithm.

theorem_wanted beckSpencerGluskinLogUpperBound_holds : beckSpencerGluskinLogUpperBound
Sources
  • optimization catalogue C24a, line 35, Beck, Spencer, and Gluskin.
Uses 1

TheoremBanaszczyk's bound for the Komlós problem#●ready to prove

There are a real constant \(c > 0\) and a natural number \(N \ge 3\) such that for every natural number \(n \ge N\), the Komlós constant in dimension \(n\) is at most \(c \sqrt{\log n}\), where \(\log\) is the natural logarithm.

theorem_wanted banaszczyk1998SqrtLogUpperBound_holds : banaszczyk1998SqrtLogUpperBound
Sources
  • optimization catalogue C24a, line 36, Banaszczyk (1998).
Uses 1

TheoremSublogarithmic bound for the Komlós problem#●ready to prove

For every real \(\varepsilon > 0\) there is a natural number \(N \ge 3\) such that for every natural number \(n \ge N\), the Komlós constant in dimension \(n\) is at most \(\varepsilon \log n\), where \(\log\) is the natural logarithm. In other words, the Komlós constant in dimension \(n\) is \(o(\log n)\).

theorem_wanted banaszczykSublogUpperBound_holds : banaszczykSublogUpperBound
Sources
  • optimization catalogue C24a, line 36, its sublogarithmic comment.
Uses 1

TheoremBansal–Dadush–Garg bound for the Komlós problem, numerical form#●ready to prove

There are a real constant \(c > 0\) and a natural number \(N \ge 3\) such that for every natural number \(n \ge N\), the Komlós constant in dimension \(n\) is at most \(c \sqrt{\log n}\), where \(\log\) is the natural logarithm.

theorem_wanted bdg2019NumericalSqrtLogUpperBound_holds : bdg2019NumericalSqrtLogUpperBound
Sources
  • BDG2019, arXiv1605.02882, retained Theorem komlos.
Uses 1

TheoremBansal–Jiang bound for the Komlós problem#●ready to prove

There are a real constant \(c > 0\), a natural number \(p\) and a natural number \(N \ge 3\) such that for every natural number \(n \ge N\), the Komlós constant in dimension \(n\) is at most \(c (\log n)^{1/4} (\log \log n)^p\), where \(\log\) is the natural logarithm.

theorem_wanted bansalJiang2025QuarterLogUpperBound_holds : bansalJiang2025QuarterLogUpperBound
Sources
  • BJ2025, arXiv2508.03961, abstract and Theorem thm:Komlos.
Uses 1

TheoremBansal–Jiang improvement on Banaszczyk's Komlós bound#●ready to prove

For every real \(\varepsilon > 0\) there is a natural number \(N \ge 3\) such that for every natural number \(n \ge N\), the Komlós constant in dimension \(n\) is at most \(\varepsilon \sqrt{\log n}\), where \(\log\) is the natural logarithm. In other words, the Komlós constant in dimension \(n\) is \(o(\sqrt{\log n})\).

theorem_wanted bansalJiang2025LittleSqrtLogUpperBound_holds :
  bansalJiang2025LittleSqrtLogUpperBound
Sources
  • BJ2025, arXiv2508.03961, the improvement reported in its abstract.
Uses 1

TheoremKunisky's lower bound for the Komlós constant#●ready to prove

The Komlós constant (the supremum over all \(n \ge 1\) of the discrepancy of real \(n \times n\) matrices whose columns all have Euclidean norm at most \(1\), taken in \([0, \infty]\)) is at least \(1 + \sqrt{2}\).

theorem_wanted kunisky2023LowerBound_holds : kunisky2023LowerBound
Sources
  • Kunisky, arXiv2111.02974v1, Theorem 1.1; catalogue C24a, line 45.
Uses 1

TheoremInfinitely many dimensions have Komlós constant at least \(1 + \sqrt{2}\)#●ready to prove

There are infinitely many natural numbers \(n \ge 1\) such that the Komlós constant in dimension \(n\) (the supremum of the discrepancy of real \(n \times n\) matrices whose columns all have Euclidean norm at most \(1\), taken in \([0, \infty]\)) is at least \(1 + \sqrt{2}\).

theorem_wanted kuniskyInfinitelyManyDimensionsLowerBound_holds :
  kuniskyInfinitelyManyDimensionsLowerBound
Sources
  • catalogue C24a, line 53, unverified exact finite-endpoint assertion.
Uses 1

TheoremNikolov's theorem: the Komlós conjecture holds for vector colorings#●ready to prove

For all natural numbers \(m\) and \(n \ge 1\) and every real \(m \times n\) matrix \(A\) whose columns all have Euclidean norm at most \(1\), there are unit vectors \(u_1, \dots, u_n\) in the Euclidean space \(\mathbb{R}^n\) such that \(\lVert \sum_{j=1}^{n} A_{ij} u_j \rVert \le 1\) for every row index \(i\), where \(\lVert \cdot \rVert\) is the Euclidean norm.

theorem_wanted nikolov2013VectorColoringBound_holds : nikolov2013VectorColoringBound
Sources
  • Nikolov, arXiv1301.4039, retained Theorem thm:main.
Uses 1

TheoremNikolov's bound on vector discrepancy#●ready to prove

For all natural numbers \(m\) and \(n\) with \(n \ge 1\) and every real \(m \times n\) matrix \(A\) whose columns all lie in the closed Euclidean unit ball, that is, \(\sum_{i} A_{ij}^2 \le 1\) for every column \(j\), the vector discrepancy of \(A\) is at most \(1\).

theorem_wanted nikolov2013VectorDiscrepancyUpperBound_holds :
  nikolov2013VectorDiscrepancyUpperBound
Sources
  • Nikolov, arXiv1301.4039, retained Theorem thm:main; catalogue line 55.
Uses 1
18 fully proved11 ready to prove

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