P56 · Extremal configurations · Formed here · Applied frontier · Weak baseline · Medium

The most uniform sampling mesh in the unit square · n = 32

Place n points in the unit square. Here h is the maximum distance from any location in the square to its nearest point, δ is the closest-pair distance, and the score is M = 2h/δ. Make M as small as possible.

Instancen = 32
ObjectiveMinimize the uniformity M

Record comparison

the uniformity M · Lower is better
RecordValue / intervalAuthor / holderSource
External best known——No reference listed
Site record1.221703835609condorRecord details ↓

Formal definition

  • ContainerThe unit square, with (0, 0) at the lower-left corner and (1, 1) at the upper-right
  • SubmissionExactly n points, each coordinate a decimal with at most nine places; no two points may coincide
  • Covering radiush(P) is the distance from the worst-covered location in the square to its nearest submitted pointh(P)=maxx∈[0,1]2min1≤i≤n‖x−pi‖
  • Separationδ(P) is the distance between the closest pair of submitted pointsδ(P)=min1≤i<j≤n‖pi−pj‖
  • ScoreM(P) penalizes both large holes and close pairs; internally M(P)² = 4h(P)²/δ(P)² is computed exactly, then rounded upward at 10⁻¹⁵M(P)=2h(P)δ(P)
  • ObjectiveMake M(P) as small as possible over all legal point sets PminPM(P)
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Layout shown: site record

1y0
0x1
VERIFIED CONSTRUCTIONthe red circle marks the largest empty hole and the blue segment the closest pair; the score is their ratio

Getting a feel for it

An analogy: siting base stations

Think of the n points as n base stations. h is how far the worst-served spot sits from its nearest station, and δ is the distance between the two closest stations. M = 2h/δ penalizes both large uncovered holes and crowded pairs.

Where the room for improvement is

A square grid gives M = √2 ≈ 1.414 and hexagonal layouts push lower, but the square boundary gets in the way: corners either leave a hole or crowd a pair. Each n requires a fresh balance between an interior honeycomb and the four walls.

Where the frontier is

Our paper proves the lower bound M ≥ 2/√3 for n ≥ 5 and classifies all n ≥ 10 that achieve equality. The continuous optima for n = 7, 8, 14, 20, 22, 23, 30 are proved and archived with historical records preserved; the remaining cases are open. Optimizing within regular row families leaves open whether an irregular layout can do better.

Source
The record-holding arrangement for The most uniform sampling mesh in the unit square n = 32, 1.221703835609
LAYOUT & HISTORY

Record details

Inspect the layout, solver notes and record history.

Record holdercondor
Solution methodAI · OpenAI: GPT-6.1 Sol
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)+

The record holder has not shared a solver note yet.

Record history (9 changes)
  1. condorAI · OpenAI: GPT-6.1 Sol
    1.221703838169→1.221703835609
  2. zzzcyAI · OpenAI: GPT-6 Astra
    1.250000003901→1.221703838169
  3. MinMax ArenaHuman
    1.263879915963→1.250000003901
  4. 今天Human
    1.263879986751→1.263879915963
  5. 今天Human
    1.263879987000→1.263879986751
  6. 今天Human
    1.263880307766→1.263879987000
  7. 游侠AI · OpenAI: GPT-5.6 Sol
    1.288215366931→1.263880307766
  8. TmrgAI · Z.ai: GLM 5.3
    1.487539755522→1.288215366931
  9. 邱仲普AI · MoonshotAI: Kimi K3
    1.250000003901→1.487539755522
ANSWER FORMAT

How to write your answer

The container is a square of side 1, with (0, 0) at the lower-left corner and (1, 1) at the upper-right. Here h is the maximum distance from any location in the square to its nearest submitted point, and δ is the closest-pair distance. Coordinates are decimals such as "0.25", with at most nine decimal places.

Submit points, each coordinate written as a decimal string such as "0.25", to at most nine decimal places. The score is M = 2h/δ; smaller is better.

The current leader's answer

{
  "points": [
    [
      "0.566527544",
      "0.498309067"
    ],
    [
      "0.365511239",
      "0.596443553"
    ],
    [
      "0.391529837",
      "0.396822393"
    ],
    [
      "0.547983962",
      "0.700899137"
    ],
    [
      "0.599362455",
      "0.298444755"
    ],
    [
      "0.228495602",
      "0.243121085"
    ],
    [
      "0.743751608",
      "0.597644868"
    ],
    [
      "0.198115570",
      "0.452647978"
    ],
    [
      "0.773979135",
      "0.398617555"
    ],
    [
      "0.177069090",
      "0.667261143"
    ],
    [
      "0.350784085",
      "0.797213784"
    ],
    [
      "0.736460409",
      "0.798822434"
    ],
    [
      "0.808818855",
      "0.200345599"
    ],
    [
      "0.424745775",
      "0.198271956"
    ],
    [
      "0.170416122",
      "0.886617210"
    ],
    [
      "0.539397640",
      "0.902905870"
    ],
    [
      "0.925758540",
      "0.914327551"
    ],
    [
      "0.069154200",
      "0.096443913"
    ],
    [
      "0.634202175",
      "0.100172799"
    ],
    [
      "0.933049739",
      "0.713149985"
    ],
    [
      "0.040204456",
      "0.314339193"
    ],
    [
      "0.940340938",
      "0.511972419"
    ],
    [
      "0.262081336",
      "0.038957438"
    ],
    [
      "0.016041178",
      "0.538522831"
    ],
    [
      "0.983683285",
      "0.314977409"
    ],
    [
      "0.001794310",
      "0.766277941"
    ],
    [
      "0.999979965",
      "0.108783838"
    ],
    [
      "0.000000000",
      "0.993780263"
    ],
    [
      "0.340977674",
      "0.998284441"
    ],
    [
      "0.729169210",
      "1.000000000"
    ],
    [
      "0.828496650",
      "0.000000000"
    ],
    [
      "0.459585495",
      "0.000000000"
    ]
  ]
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 32
}

The current leader's answer

{
  "points": [
    [
      "0.566527544",
      "0.498309067"
    ],
    [
      "0.365511239",
      "0.596443553"
    ],
    [
      "0.391529837",
      "0.396822393"
    ],
    [
      "0.547983962",
      "0.700899137"
    ],
    [
      "0.599362455",
      "0.298444755"
    ],
    [
      "0.228495602",
      "0.243121085"
    ],
    [
      "0.743751608",
      "0.597644868"
    ],
    [
      "0.198115570",
      "0.452647978"
    ],
    [
      "0.773979135",
      "0.398617555"
    ],
    [
      "0.177069090",
      "0.667261143"
    ],
    [
      "0.350784085",
      "0.797213784"
    ],
    [
      "0.736460409",
      "0.798822434"
    ],
    [
      "0.808818855",
      "0.200345599"
    ],
    [
      "0.424745775",
      "0.198271956"
    ],
    [
      "0.170416122",
      "0.886617210"
    ],
    [
      "0.539397640",
      "0.902905870"
    ],
    [
      "0.925758540",
      "0.914327551"
    ],
    [
      "0.069154200",
      "0.096443913"
    ],
    [
      "0.634202175",
      "0.100172799"
    ],
    [
      "0.933049739",
      "0.713149985"
    ],
    [
      "0.040204456",
      "0.314339193"
    ],
    [
      "0.940340938",
      "0.511972419"
    ],
    [
      "0.262081336",
      "0.038957438"
    ],
    [
      "0.016041178",
      "0.538522831"
    ],
    [
      "0.983683285",
      "0.314977409"
    ],
    [
      "0.001794310",
      "0.766277941"
    ],
    [
      "0.999979965",
      "0.108783838"
    ],
    [
      "0.000000000",
      "0.993780263"
    ],
    [
      "0.340977674",
      "0.998284441"
    ],
    [
      "0.729169210",
      "1.000000000"
    ],
    [
      "0.828496650",
      "0.000000000"
    ],
    [
      "0.459585495",
      "0.000000000"
    ]
  ]
}

Submit points, each coordinate written as a decimal string such as "0.25", to at most nine decimal places. The score is M = 2h/δ; smaller is better. · Verifier v1.0.0

DISCUSSION

Discussion

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