P22 · Extremal configurations · Classic

The smallest triangle in a disc · n = 14

Place n points inside a circle of radius 1 so that the smallest triangle formed by any three of them is as large as possible.

Instancen = 14
ObjectiveMaximize the smallest triangle's area

Formal definition

  • ContainerThe container is a circle of radius 1 centred at (1, 1), so coordinates run from 0 to 2.
  • SubmissionExactly n points, no three collinear
  • ConstraintsEvery point lies inside the container or on its boundary
  • ObjectiveMake the smallest triangle over all triples as large as possible; compared internally by twice the area, exactly
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2y0
0x2
VERIFIED CONSTRUCTIONthe smallest triangle

Getting a feel for it

Where the room for improvement is

Even spreading is not enough: no three points may come close to collinear, and near-collinearity is exactly what tidy arrangements love to do. Optima are often asymmetric and hard even to guess.

Where the frontier is

Heilbronn in a disc: MathWorld collects the known values, some in closed form, none proven; the proof techniques from the square version have not been carried over.

Source
Current leader

0.027499518584008526

the smallest triangle's area

Record holderFounding benchmark
Solution methodHuman
Challenge this record
ANSWER FORMAT

How to write your answer

The container is a circle of radius 1 centred at (1, 1), so coordinates run from 0 to 2. Coordinates are written as plain decimals such as "0.5", to at most nine decimal places.

Submit points, each coordinate written as a decimal string such as "0.5".

The current leader's answer

{
  "points": [
    [
      "1.8",
      "1"
    ],
    [
      "1.720775094",
      "1.347106991"
    ],
    [
      "1.498791841",
      "1.625465186"
    ],
    [
      "1.178016747",
      "1.77994233"
    ],
    [
      "0.821983253",
      "1.77994233"
    ],
    [
      "0.501208159",
      "1.625465186"
    ],
    [
      "0.279224906",
      "1.347106991"
    ],
    [
      "0.2",
      "1"
    ],
    [
      "0.279224906",
      "0.652893009"
    ],
    [
      "0.501208159",
      "0.374534814"
    ],
    [
      "0.821983253",
      "0.22005767"
    ],
    [
      "1.178016747",
      "0.22005767"
    ],
    [
      "1.498791841",
      "0.374534814"
    ],
    [
      "1.720775094",
      "0.652893009"
    ]
  ]
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer

Instance parameters

{
  "n": 14
}

The current leader's answer

{
  "points": [
    [
      "1.8",
      "1"
    ],
    [
      "1.720775094",
      "1.347106991"
    ],
    [
      "1.498791841",
      "1.625465186"
    ],
    [
      "1.178016747",
      "1.77994233"
    ],
    [
      "0.821983253",
      "1.77994233"
    ],
    [
      "0.501208159",
      "1.625465186"
    ],
    [
      "0.279224906",
      "1.347106991"
    ],
    [
      "0.2",
      "1"
    ],
    [
      "0.279224906",
      "0.652893009"
    ],
    [
      "0.501208159",
      "0.374534814"
    ],
    [
      "0.821983253",
      "0.22005767"
    ],
    [
      "1.178016747",
      "0.22005767"
    ],
    [
      "1.498791841",
      "0.374534814"
    ],
    [
      "1.720775094",
      "0.652893009"
    ]
  ]
}

Submit points, each coordinate written as a decimal string such as "0.5". · Verifier v1.0.0