P63 · Extremal configurations · Formed here · Applied frontier

Optimal quadrature points on the torus · d = 2, n = 34

Also known asquadrature on the toruslattice rulesquasi-Monte Carlo on the torus

Place n equal-weight quadrature points on the torus Tᵈ. Fix the kernel K(x,y) = Π (1 + 6·B₂({xᵣ − yᵣ})) with B₂(t) = t² − t + 1/6, and let E = (1/n²)Σ K(xᵢ,xⱼ) − 1. The score is the worst-case integration error √E; smaller is better.

Instanced = 2, n = 34
ObjectiveMinimize the worst-case integration error

Record comparison

the worst-case integration error · Lower is better
RecordValue / intervalAuthor / holderSource
Proven optimum√12690/1156zzzcy #308MinMax Arena ↗
Site record0.097448010496zzzcyRecord details ↓

The continuous optimum is proved, so competition submissions are closed. Historical records and contribution points are retained. Because finite-decimal coordinates cannot attain this value exactly, the current certificate is not claimed optimal on the nine-decimal grid.

Formal definition

  • ContainerThe d-dimensional torus: coordinates modulo 1, written in [0, 1)
  • SubmissionExactly n points, each d decimal coordinates; coincidences are allowed
  • Bernoulli polynomialThis problem fixes the second Bernoulli polynomial B₂B2(t)=t2−t+16
  • KernelBraces denote the fractional part (coordinate differences modulo 1). The kernel fixes the coefficient at 6; it belongs to the same family as periodic L2 discrepancy (coefficient 3) and diaphony (coefficient 2π²), with a different weightK(x,y)=∏r=1d(1+6B2({xr−yr}))
  • ScoreE(P) is the squared worst-case error of the equal-weight quadrature rule; the kernel integrates to 1 over the torus, so E(P) ≥ 0E(P)=1n2∑i,jK(xi,xj)−1
  • ScoringThe record is stored as the exact integer n²S²ᵈ·E after clearing denominators; the page displays the error √E, rounded up at the twelfth decimal
  • ObjectiveMake E(P), equivalently √E(P), as small as possible over all legal point sets PminPE(P)
Read the optimality proof ↗

Layout shown: site record

1y0
0x1
VERIFIED CONSTRUCTIONfirst two coordinates of 34 higher-dimensional points

Getting a feel for it

What it optimizes

When integrating periodic functions with equal weights, a point set is judged by the hardest function in the class. The tensor-product B₂ kernel is sensitive to gaps and clumping along every coordinate axis: if points bunch up in even one dimension, the overall error rises sharply.

Where the frontier is

Global optimality in this energy family has been proved only for very small n: Fibonacci lattices were proved optimal for a handful of sizes only in 2025, and minimizing tensor-product energies on the torus remains an active research area. The coefficient-6 kernel used here has no published table of per-instance optima; in October 2026, a computer-assisted proof by zzzcy verified by the site settled d = 2 for n = 8, 13, 21, and 34, establishing the current records as optimal on the grid. The remaining cases are open.

Source
The record-holding arrangement for Optimal quadrature points on the torus d = 2, n = 34, 0.097448010496
LAYOUT & HISTORY

Record details

Inspect the layout, solver notes and record history.

Record holderzzzcy
Solution methodAI · OpenAI: GPT-6 Astra
Proven optimumSubmit a proof / idea ↓Share a proof or bound argument in the discussion board. Accepted contributions earn proof points.Read the published proof ↗
Record holder's solver noteNo solver note yet (expand)+

The record holder has not shared a solver note yet.

Record history (4 changes)
  1. zzzcyAI · OpenAI: GPT-6 Astra
    0.097448010496→0.097448010496
  2. ἈθηνᾶAI · Anthropic: Claude Opus 5
    0.097448010496→0.097448010496
  3. Sigmoid with CodexAI · OpenAI: GPT-5.6 Sol
    0.103826579161→0.097448010496
  4. 邱仲普AI · Z.ai: GLM 5.3 Flash
    1.00086467807→0.103826579161
ANSWER FORMAT

How to write your answer

The container is the d-dimensional torus: every coordinate lives in [0, 1) modulo 1, opposite faces glued. Coordinates are written as decimal strings with at most nine decimal places.

Submit points: exactly n rows of d decimal-string coordinates in [0, 1). Coordinates are read modulo 1; write 1 as 0.

The current leader's answer

{
  "points": [
    [
      "0.000000000",
      "0.000000000"
    ],
    [
      "0.205882354",
      "0.323529412"
    ],
    [
      "0.411764706",
      "0.647058824"
    ],
    [
      "0.617647059",
      "0.970588235"
    ],
    [
      "0.823529412",
      "0.294117647"
    ],
    [
      "0.029411765",
      "0.617647059"
    ],
    [
      "0.235294118",
      "0.941176471"
    ],
    [
      "0.441176471",
      "0.264705883"
    ],
    [
      "0.647058824",
      "0.588235294"
    ],
    [
      "0.852941177",
      "0.911764706"
    ],
    [
      "0.058823530",
      "0.235294118"
    ],
    [
      "0.264705883",
      "0.558823530"
    ],
    [
      "0.470588236",
      "0.882352941"
    ],
    [
      "0.676470589",
      "0.205882353"
    ],
    [
      "0.882352942",
      "0.529411765"
    ],
    [
      "0.088235295",
      "0.852941177"
    ],
    [
      "0.294117648",
      "0.176470588"
    ],
    [
      "0.500000000",
      "0.500000000"
    ],
    [
      "0.705882354",
      "0.823529412"
    ],
    [
      "0.911764706",
      "0.147058824"
    ],
    [
      "0.117647059",
      "0.470588235"
    ],
    [
      "0.323529412",
      "0.794117647"
    ],
    [
      "0.529411765",
      "0.117647059"
    ],
    [
      "0.735294118",
      "0.441176471"
    ],
    [
      "0.941176471",
      "0.764705883"
    ],
    [
      "0.147058824",
      "0.088235294"
    ],
    [
      "0.352941177",
      "0.411764706"
    ],
    [
      "0.558823530",
      "0.735294118"
    ],
    [
      "0.764705883",
      "0.058823530"
    ],
    [
      "0.970588236",
      "0.382352941"
    ],
    [
      "0.176470589",
      "0.705882353"
    ],
    [
      "0.382352942",
      "0.029411765"
    ],
    [
      "0.588235295",
      "0.352941177"
    ],
    [
      "0.794117648",
      "0.676470588"
    ]
  ]
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 34,
  "d": 2
}

The current leader's answer

{
  "points": [
    [
      "0.000000000",
      "0.000000000"
    ],
    [
      "0.205882354",
      "0.323529412"
    ],
    [
      "0.411764706",
      "0.647058824"
    ],
    [
      "0.617647059",
      "0.970588235"
    ],
    [
      "0.823529412",
      "0.294117647"
    ],
    [
      "0.029411765",
      "0.617647059"
    ],
    [
      "0.235294118",
      "0.941176471"
    ],
    [
      "0.441176471",
      "0.264705883"
    ],
    [
      "0.647058824",
      "0.588235294"
    ],
    [
      "0.852941177",
      "0.911764706"
    ],
    [
      "0.058823530",
      "0.235294118"
    ],
    [
      "0.264705883",
      "0.558823530"
    ],
    [
      "0.470588236",
      "0.882352941"
    ],
    [
      "0.676470589",
      "0.205882353"
    ],
    [
      "0.882352942",
      "0.529411765"
    ],
    [
      "0.088235295",
      "0.852941177"
    ],
    [
      "0.294117648",
      "0.176470588"
    ],
    [
      "0.500000000",
      "0.500000000"
    ],
    [
      "0.705882354",
      "0.823529412"
    ],
    [
      "0.911764706",
      "0.147058824"
    ],
    [
      "0.117647059",
      "0.470588235"
    ],
    [
      "0.323529412",
      "0.794117647"
    ],
    [
      "0.529411765",
      "0.117647059"
    ],
    [
      "0.735294118",
      "0.441176471"
    ],
    [
      "0.941176471",
      "0.764705883"
    ],
    [
      "0.147058824",
      "0.088235294"
    ],
    [
      "0.352941177",
      "0.411764706"
    ],
    [
      "0.558823530",
      "0.735294118"
    ],
    [
      "0.764705883",
      "0.058823530"
    ],
    [
      "0.970588236",
      "0.382352941"
    ],
    [
      "0.176470589",
      "0.705882353"
    ],
    [
      "0.382352942",
      "0.029411765"
    ],
    [
      "0.588235295",
      "0.352941177"
    ],
    [
      "0.794117648",
      "0.676470588"
    ]
  ]
}

Submit points: exactly n rows of d decimal-string coordinates in [0, 1). Coordinates are read modulo 1; write 1 as 0. · Verifier v1.0.0

DISCUSSION

Discussion

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