P82 · Packing and covering · Classic · Hard

Equal circles in regular polygons · m = 5 · n = 37

Pack n equal circles into the true regular m-gon with centre (1,1), circumradius 1 and first vertex (2,1), maximising their radius.

Instancem = 5 · n = 37
ObjectiveMaximize circle radius

Formal definition

  • ContainerThe editor and certificate normalize to the true regular m-gon with centre (1,1), circumradius 1 and first vertex (2,1). This is a coordinate convention only; scores use the literature's unit-piece scale. Boundary contact is allowed.
  • SubmissionSubmit {radius, placements:[{x,y,turn},…]}, with decimal strings of at most nine places. x,y are centres; circles require turn=0, polygons use turn=tan(θ/2). Coordinates and turn lie in ±4; 0 < radius ≤ 4.
  • ConstraintsExactly n congruent shapes lie wholly in the container with pairwise disjoint interiors. Polygon rotations are independent, not limited to quarter turns.
  • PrecisionInput decimals are exact rationals; regular-polygon vertices are algebraic, not rounded templates. Feasibility has no floating-point tolerance. A finite-decimal certificate is not a continuous optimality proof.
  • ObjectiveCircle radius r, larger is better; the container circumradius is 1.
Open the full editor
VERIFIED CONSTRUCTIONVERIFIED CONSTRUCTION

Getting a feel for it

Source and certificate

External targets are converted with their printed precision; decimal coordinate certificates are separate. Reconstruction loss never lowers the literature target, and a source construction is not automatically an optimality proof.

Source
The record-holding arrangement for Equal circles in regular polygons m = 5 · n = 37, 0.126679668
Current leader

0.126679668

circle radius

Answer sourcePaolo Amore
Solution methodPublished reference construction
Challenge this record Submit a proof / idea Share a proof or idea in the discussion. Accepted contributions can earn proof points.
Record holder's solver noteNo solver note yet (expand)

The record holder has not shared a solver note yet.

ANSWER FORMAT

How to write your answer

the true regular m-gon with centre (1,1), circumradius 1 and first vertex (2,1)

Submit {radius, placements:[{x,y,turn},…]}, with decimal strings of at most nine places. x,y are centres; circles require turn=0, polygons use turn=tan(θ/2). Coordinates and turn lie in ±4; 0 < radius ≤ 4.

The current leader's answer

{
  "placements": [
    {
      "turn": "0",
      "x": "0.317662674",
      "y": "1.348995033"
    },
    {
      "turn": "0",
      "x": "0.317662674",
      "y": "1.013445114"
    },
    {
      "turn": "0",
      "x": "0.317662674",
      "y": "0.760085777"
    },
    {
      "turn": "0",
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      "y": "0.506726439"
    },
    {
      "turn": "0",
      "x": "0.475634694",
      "y": "1.547075306"
    },
    {
      "turn": "0",
      "x": "0.507511343",
      "y": "1.181220074"
    },
    {
      "turn": "0",
      "x": "0.557884385",
      "y": "0.932918824"
    },
    {
      "turn": "0",
      "x": "0.557884385",
      "y": "0.679559487"
    },
    {
      "turn": "0",
      "x": "0.557884385",
      "y": "0.426200149"
    },
    {
      "turn": "0",
      "x": "0.668882313",
      "y": "1.376541255"
    },
    {
      "turn": "0",
      "x": "0.716593743",
      "y": "1.625367647"
    },
    {
      "turn": "0",
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      "y": "1.130557316"
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    {
      "turn": "0",
      "x": "0.777300008",
      "y": "0.806239155"
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    {
      "turn": "0",
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      "y": "0.552879818"
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    {
      "turn": "0",
      "x": "0.880350534",
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    {
      "turn": "0",
      "x": "0.909841361",
      "y": "1.454833596"
    },
    {
      "turn": "0",
      "x": "0.957552792",
      "y": "1.703659988"
    },
    {
      "turn": "0",
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    {
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    {
      "turn": "0",
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    {
      "turn": "0",
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    {
      "turn": "0",
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    {
      "turn": "0",
      "x": "1.188479312",
      "y": "0.845142229"
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    {
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    {
      "turn": "0",
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      "y": "1.786135624"
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    {
      "turn": "0",
      "x": "1.228976394",
      "y": "1.095244088"
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    {
      "turn": "0",
      "x": "1.291529838",
      "y": "0.613686957"
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    {
      "turn": "0",
      "x": "1.303181009",
      "y": "1.337493193"
    },
    {
      "turn": "0",
      "x": "1.394580365",
      "y": "0.382231685"
    },
    {
      "turn": "0",
      "x": "1.397306092",
      "y": "1.614016673"
    },
    {
      "turn": "0",
      "x": "1.440450720",
      "y": "0.818658966"
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    {
      "turn": "0",
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      "y": "1.068760826"
    },
    {
      "turn": "0",
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      "y": "0.587203694"
    },
    {
      "turn": "0",
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      "y": "1.409044663"
    },
    {
      "turn": "0",
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    },
    {
      "turn": "0",
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    },
    {
      "turn": "0",
      "x": "1.841343011",
      "y": "0.997147714"
    }
  ],
  "radius": "0.126679668"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer

Instance parameters

{
  "n": 37,
  "sides": 5
}

The current leader's answer

{
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      "y": "1.348995033"
    },
    {
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    },
    {
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    },
    {
      "turn": "0",
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    },
    {
      "turn": "0",
      "x": "0.507511343",
      "y": "1.181220074"
    },
    {
      "turn": "0",
      "x": "0.557884385",
      "y": "0.932918824"
    },
    {
      "turn": "0",
      "x": "0.557884385",
      "y": "0.679559487"
    },
    {
      "turn": "0",
      "x": "0.557884385",
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    {
      "turn": "0",
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    {
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    {
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    {
      "turn": "0",
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      "y": "0.321424546"
    },
    {
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    {
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    {
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    {
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    {
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    {
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    },
    {
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    },
    {
      "turn": "0",
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    {
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    {
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    {
      "turn": "0",
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    {
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    },
    {
      "turn": "0",
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    },
    {
      "turn": "0",
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      "y": "0.997147714"
    }
  ],
  "radius": "0.126679668"
}

Submit {radius, placements:[{x,y,turn},…]}, with decimal strings of at most nine places. x,y are centres; circles require turn=0, polygons use turn=tan(θ/2). Coordinates and turn lie in ±4; 0 < radius ≤ 4. · Verifier v1.0.0

DISCUSSION

Discussion

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