P33 · Extremal configurations · Classic · Weak baseline

Riesz 2-energy in a square

1y0
0x1
VERIFIED CONSTRUCTIONthe closest pair
n = 10Current record · open

Place n points inside the unit square, minimizing the sum of 1/distance² taken over every pair.

Formal definition

  • ContainerThe container is a square of side 1, with the origin (0, 0) at its lower-left corner and (1, 1) at its upper-right.
  • SubmissionExactly n points, no two coinciding
  • ConstraintsEvery point lies inside the container or on its boundary
  • ObjectiveMake the sum of 1/distance² over all pairs as small as possible; scored in exact rationals

Getting a feel for it

Where the room for improvement is

1/distance² punishes closeness brutally: points get pushed out to a boundary ring first, then shed inner layers as n grows. Layer counts jump at particular n, and the jumps are where the contest lives.

Where the frontier is

The general theory of pairwise 1/r² energy (asymptotics, separation) is Borodachov, Hardin and Saff, Discrete Energy on Rectifiable Sets (2019); a per-n table of optima in the square does not exist, and every n here is open. The few trivial closed forms are proved on site.

Source
ONE LEADERBOARD PER n

Current best solutions by n

Each n is an independent record with a page of its own. Open any of them to inspect the current construction, then challenge it.

n5
CURRENT RECORD13best known 13
Matches the best known
Record holderFounding benchmark
Solution methodHuman
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n6
CURRENT RECORD25.2best known 25.2
Matches the best known
Record holderFounding benchmark
Solution methodHuman
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n7
CURRENT RECORD38.72000185
Record holderlird
Solution methodHuman
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n8
CURRENT RECORD53.4best known 53.4
Matches the best known
Record holderFounding benchmark
Solution methodHuman
View problem
n9
CURRENT RECORD77.4best known 77.4
Matches the best known
Record holderFounding benchmark
Solution methodHuman
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n10
CURRENT RECORD110.659971417
Record holderAnonymous
Solution methodAI · OpenAI: GPT-5.6 Sol Pro
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n11
CURRENT RECORD145.60615387
Record holderlird
Solution methodHuman
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n12
CURRENT RECORD199.001407044
Record holderlird
Solution methodHuman
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n13
CURRENT RECORD254.555555556
Record holderlird
Solution methodHuman
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n14
CURRENT RECORD315.430867468
Record holderlird
Solution methodHuman
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n15
CURRENT RECORD355.861648888
Record holderlird
Solution methodHuman
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n16
CURRENT RECORD410.538461654
Record holderlird
Solution methodHuman
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n17
CURRENT RECORD495.822353875
Record holderlird
Solution methodHuman
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n18
CURRENT RECORD21240.783810976
Record holderFounding benchmark
Solution methodHuman
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n19
CURRENT RECORD23223.433383629
Record holderFounding benchmark
Solution methodHuman
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n20
CURRENT RECORD733.767756041
Record holderlird
Solution methodHuman
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n21
CURRENT RECORD904.027963697
Record holderlird
Solution methodHuman
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n22
CURRENT RECORD28191.640271523
Record holderFounding benchmark
Solution methodHuman
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n23
CURRENT RECORD30309.682001038
Record holderFounding benchmark
Solution methodHuman
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n24
CURRENT RECORD1224.183951752
Record holderlird
Solution methodHuman
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