P54 · Extremal configurations · Classic · Applied frontier · Weak baseline

Minimum star discrepancy in the unit square

Also known asstar discrepancyminimum star discrepancylow-discrepancy point set

1y0
0x1
VERIFIED CONSTRUCTIONthe dashed box covers 59.3% of the square (expected 14.2 points, actual 13); the discrepancy 0.0516 sets the score
n = 24Current record · open

Place n points in the unit square [0, 1]². For every origin-anchored half-open rectangle [0, u) × [0, v), compare the fraction of points inside the box with its area uv, and minimize the supremum discrepancy D* over all such rectangles.

Formal definition

  • ContainerThe unit square [0, 1]², with lower-left corner at (0, 0) and upper-right corner at (1, 1)
  • SubmissionExactly n distinct points, each coordinate written as a decimal string with at most nine decimal places
  • RectanglesTest rectangles are half-open boxes [0, u) × [0, v) with (u, v) ∈ [0, 1]²; points on the top or right boundary count as outside
  • Star discrepancyThe indicator 𝟙 is 1 when the point lies in [0, u) × [0, v) and 0 otherwise; D*(P) is the supremum absolute difference between the point fraction and the area uvD∗(P)=sup(u,v)∈[0,1]2|1n∑i=1n𝟙[xi<u,yi<v]−uv|
  • ObjectiveMinimize D*(P) over all valid point sets P. The verifier evaluates the open and closed one-sided limits on the grid induced by the submitted coordinates and compares exact integersminPD∗(P)

Getting a feel for it

Spreading points evenly

If a rectangle covers 30% of the square, ideally it should contain 30% of the points on average. This problem checks every origin-anchored rectangle and scores the worst mismatch, so the goal is to distribute the points as evenly as possible across all prefix rectangles.

Why regular grids lose

The rules allow multiple points in the same row or column, but doing so hurts the score: if several points share an x-coordinate, the moment a rectangle's right edge crosses it, those points all enter the box at once, causing a jump in the point fraction while the area grows continuously. Good configurations stagger both coordinates so no two points share a coordinate.

Known results

Optimal point sets for n ≤ 21 were proven by Clément, Doerr, Klamroth, and Paquete in 2025 (Proc. Amer. Math. Soc. Ser. B 12: 78–90). This problem therefore starts at n = 22, and every instance from n = 22 upward remains open.

ONE LEADERBOARD PER n

Current best solutions by n

Each parameter n is an independently scored sub-problem. Select any card to inspect the current record construction or submit a stronger solution.

Discussion (1) ↓
n22
CURRENT RECORD0.055944055944296
Medium
Record holdercondor
Solution methodAI · OpenAI: GPT-6.1 Sol
n23
CURRENT RECORD0.053547547237373
Medium
Record holdercondor
Solution methodAI · OpenAI: GPT-6.1 Sol
n24
CURRENT RECORD0.051553672409501
Medium
Record holdercondor
Solution methodAI · OpenAI: GPT-6.1 Sol
n25
CURRENT RECORD0.049491525423802
Medium
Record holderzzzcy
Solution methodAI · OpenAI: GPT-6 Astra
n26
CURRENT RECORD0.047949110658295
Medium
Record holdercondor
Solution methodAI · OpenAI: GPT-6.1 Sol
n27
CURRENT RECORD0.046296296482946
Medium
Record holdercondor
Solution methodAI · OpenAI: GPT-6.1 Sol
n28
CURRENT RECORD0.044659496819202
Medium
Record holderzzzcy
Solution methodAI · OpenAI: GPT-6 Astra
n29
CURRENT RECORD0.043734975526926
Medium
Record holderzzzcy
Solution methodAI · OpenAI: GPT-6 Astra
n30
CURRENT RECORD0.042330063603910
Medium
Record holdercondor
Solution methodAI · OpenAI: GPT-6.1 Sol
n31
CURRENT RECORD0.041023842931929
Medium
Record holdercondor
Solution methodAI · OpenAI: GPT-6.1 Terra
n32
CURRENT RECORD0.040038063652755
Medium
Record holdercondor
Solution methodAI · OpenAI: GPT-6.1 Sol
n33
CURRENT RECORD0.038834045151516
Medium
Record holdercondor
Solution methodAI · OpenAI: GPT-6.1 Sol
n34
CURRENT RECORD0.037790213064876
Medium
Record holder邱仲普
Solution methodAI · OpenAI: GPT-5.6 Sol
n35
CURRENT RECORD0.036879504921581
Medium
Record holdercondor
Solution methodAI · OpenAI: GPT-6.1 Sol
n36
CURRENT RECORD0.035926820120929
Medium
Record holderzzzcy
Solution methodAI · OpenAI: GPT-6 Astra
n37
CURRENT RECORD0.034976152895021
Medium
Record holderzzzcy
Solution methodAI · OpenAI: GPT-6 Astra
n38
CURRENT RECORD0.034330651117681
Medium
Record holdercondor
Solution methodAI · OpenAI: GPT-6.1 Sol
n39
CURRENT RECORD0.033489742581163
Medium
Record holdercondor
Solution methodAI · OpenAI: GPT-6.1 Sol
n40
CURRENT RECORD0.032653061984975
Medium
Record holderzzzcy
Solution methodAI · OpenAI: GPT-6 Astra
n41
CURRENT RECORD0.031856645499737
Medium
Record holder邱仲普
Solution methodAI · OpenAI: GPT-5.6 Sol
n42
CURRENT RECORD0.031408308023611
Medium
Record holdercondor
Solution methodAI · OpenAI: GPT-6.1 Terra
n43
CURRENT RECORD0.030818680280013
Medium
Record holderzzzcy
Solution methodAI · OpenAI: GPT-6 Astra
n44
CURRENT RECORD0.030161427358826
Medium
Record holderzzzcy
Solution methodAI · OpenAI: GPT-6 Astra
n45
CURRENT RECORD0.029505135387545
Medium
Record holderzzzcy
Solution methodAI · OpenAI: GPT-6 Astra
n46
CURRENT RECORD0.028863719936129
Medium
Record holder邱仲普
Solution methodAI · OpenAI: GPT-5.6 Sol
n47
CURRENT RECORD0.028368794743443
Medium
Record holder邱仲普
Solution methodAI · OpenAI: GPT-5.6 Sol
n48
CURRENT RECORD0.027842679827525
Medium
Record holderzzzcy
Solution methodAI · OpenAI: GPT-6 Astra
n49
CURRENT RECORD0.027323326024992
Medium
Record holderzzzcy
Solution methodAI · OpenAI: GPT-6 Astra
n50
CURRENT RECORD0.026776859504586
Medium
Record holderzzzcy
Solution methodAI · OpenAI: GPT-6 Astra

Data and citation

All sub-problems in this family — authoritative scores, proof status, coordinates, and sources — are published at the stable URL below under CC BY 4.0. Because scores update as records fall, please cite the file's generatedAt timestamp.

GET https://minmaxarena.com/data/star-discrepancy.json

Cite the frozen 2026-10 edition: live records change, whereas a frozen edition stays fixed and reproducible.

GET https://minmaxarena.com/data/editions/2026-10/star-discrepancy.json
BibTeX (click to copy)
@misc{minmaxarena-star-discrepancy-2026-10,
  title  = {{Minimum star discrepancy in the unit square} (P54)},
  author = {{MinMax Arena}},
  year   = {2026},
  note   = {Machine-verified records, 2026-10 edition},
  url    = {https://minmaxarena.com/data/editions/2026-10/star-discrepancy.json},
  license = {CC BY 4.0}
}
DISCUSSION

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