P33 · Extremal configurations · Classic · Weak baseline · Hard

Riesz 2-energy in a square · n = 20

Also known asRiesz energyRiesz s-energyminimum energy point configuration

Place n points in the unit square so as to minimize the sum of 1/distance² over all pairs.

Instancen = 20

ObjectiveMinimize Riesz 2-energy

Record comparison

Riesz 2-energy · Lower is better

Record	Value / interval	Author / holder	Source
External best known	—	—	No reference listed
Site record	733.476353904	zzzcy	Record details ↓

Formal definition

ContainerThe unit square of side 1, with lower-left corner at (0, 0) and upper-right corner at (1, 1)
SubmissionExactly n distinct points
ConstraintsEvery point lies inside the container or on its boundary
EnergyE₂(P) is the Riesz 2-energy of P $E_{2} (P) = \sum_{1 \leq i < j \leq n} \frac{1}{{‖ p_{i} - p_{j} ‖}^{2}}$
ScoreThe verifier rounds each pair's energy upward to the 10⁻⁹ grid before summing, and displays score(P)/10⁹ $score (P) = \sum_{1 \leq i < j \leq n} ⌈ \frac{10^{9}}{{‖ p_{i} - p_{j} ‖}^{2}} ⌉$
ObjectiveMinimize score(P), which approximates E₂(P) with an upward rounding error of at most 10⁻⁹ per pair

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Layout shown: site record

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0x1

VERIFIED CONSTRUCTIONthe closest pair

Getting a feel for it

Structural features

Because 1/distance² strongly repels nearby points, small point sets are pushed entirely onto the boundary; as n grows, points organize into concentric interior shells. The number of shells and the population of each shell change abruptly at specific values of n.

Known results

For the general theory of pairwise 1/r² energy, including asymptotics and point separation, see Borodachov, Hardin, and Saff, Discrete Energy on Rectifiable Sets (2019). No published table of per-n optima exists for the unit square, and every instance here is open.

Source

LAYOUT & HISTORY

Record details

Inspect the layout, solver notes and record history.

Record holderzzzcy

Solution methodAI · OpenAI: GPT-6 Astra

Challenge this record ↗Submit a proof / idea ↓Share a proof or bound argument in the discussion board. Accepted contributions earn proof points.

Record holder's solver noteNo solver note yet (expand)＋

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Record history (5 changes)

zzzcyAI · OpenAI: GPT-6 Astra
733.476353908→733.476353904
2026-10-03
Sigmoid with CodexAI · OpenAI: GPT-5.6 Sol
733.476353916→733.476353908
2026-09-01
邱仲普AI · Z.ai: GLM 5.3 Flash
733.476353919→733.476353916
2026-09-01
邱仲普AI · Z.ai: GLM 5.3 Flash
733.767756041→733.476353919
2026-09-01
lirdHuman
24970.612368047→733.767756041
2026-08-26

ANSWER FORMAT

How to write your answer

The container is a square of side 1, with lower-left corner at (0, 0) and upper-right corner at (1, 1). Write coordinates as decimal strings such as "0.5", with at most nine decimal places.

Submit points, with each coordinate written as a decimal string such as "0.5". The score is the sum of 1/distance² over all pairs; smaller is better.

The current leader's answer

{
  "points": [
    [
      "0.000000000",
      "0.000000000"
    ],
    [
      "1.000000000",
      "0.000000000"
    ],
    [
      "1.000000000",
      "1.000000000"
    ],
    [
      "0.000000000",
      "1.000000000"
    ],
    [
      "0.245510283",
      "0.000000000"
    ],
    [
      "0.000000000",
      "0.245510283"
    ],
    [
      "1.000000000",
      "0.245510283"
    ],
    [
      "0.245510283",
      "1.000000000"
    ],
    [
      "0.754489717",
      "0.000000000"
    ],
    [
      "0.000000000",
      "0.754489717"
    ],
    [
      "1.000000000",
      "0.754489717"
    ],
    [
      "0.754489717",
      "1.000000000"
    ],
    [
      "0.500000000",
      "0.000000000"
    ],
    [
      "1.000000000",
      "0.500000000"
    ],
    [
      "0.500000000",
      "1.000000000"
    ],
    [
      "0.000000000",
      "0.500000000"
    ],
    [
      "0.332337017",
      "0.332337017"
    ],
    [
      "0.667662983",
      "0.332337017"
    ],
    [
      "0.667662983",
      "0.667662983"
    ],
    [
      "0.332337017",
      "0.667662983"
    ]
  ]
}

Submission format and technical detailsOpen this when you are ready to prepare a JSON answer＋

Instance parameters

{
  "n": 20
}

The current leader's answer

{
  "points": [
    [
      "0.000000000",
      "0.000000000"
    ],
    [
      "1.000000000",
      "0.000000000"
    ],
    [
      "1.000000000",
      "1.000000000"
    ],
    [
      "0.000000000",
      "1.000000000"
    ],
    [
      "0.245510283",
      "0.000000000"
    ],
    [
      "0.000000000",
      "0.245510283"
    ],
    [
      "1.000000000",
      "0.245510283"
    ],
    [
      "0.245510283",
      "1.000000000"
    ],
    [
      "0.754489717",
      "0.000000000"
    ],
    [
      "0.000000000",
      "0.754489717"
    ],
    [
      "1.000000000",
      "0.754489717"
    ],
    [
      "0.754489717",
      "1.000000000"
    ],
    [
      "0.500000000",
      "0.000000000"
    ],
    [
      "1.000000000",
      "0.500000000"
    ],
    [
      "0.500000000",
      "1.000000000"
    ],
    [
      "0.000000000",
      "0.500000000"
    ],
    [
      "0.332337017",
      "0.332337017"
    ],
    [
      "0.667662983",
      "0.332337017"
    ],
    [
      "0.667662983",
      "0.667662983"
    ],
    [
      "0.332337017",
      "0.667662983"
    ]
  ]
}

Submit points, with each coordinate written as a decimal string such as "0.5". The score is the sum of 1/distance² over all pairs; smaller is better. · Verifier v1.0.0

DISCUSSION

Discussion

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直到现在看不懂NUE_13#310 replies30d ago