The Heilbronn Problem

math.tejstead.com · 2026-10-04 · by Long Nguyen ·generic
The Heilbronn problem for squares, triangles and convex regions: best known configurations with exact coordinates, proofs, and an interactive viewer.

The Heilbronn Problem

The Heilbronn Problem

Place n points in a unit-area region such that the smallest triangle determined by any three points achieves the largest possible area, A(n).

This site collects the best known configurations across three classic containers: the square, the triangle, and optimal convex regions. Each entry includes exact coordinates, symmetry and congruence analysis, references to published proofs, and an in-browser rational arithmetic verifier.

Squares Triangles Convex regions

Recent records

| date | entry | new value | gain | found by | | ---------- | -------------------------------------------------------------------- | ---------- | ------ | ---------------------------------------- | | 2026-10-01 | Triangle, n = 20 | 0.01260939 | +2.37% | Rob Gardiner | | 2026-10-01 | Square, n = 23 | 0.00975728 | +1.18% | Rob Gardiner | | 2026-09-28 | Square, n = 21 | 0.01147376 | +1.85% | Rob Gardiner | | 2026-09-28 | Square, n = 23 | 0.00964331 | +1.97% | Rob Gardiner | | 2026-09-28 | Square, n = 25 | 0.00823006 | +3.74% | Rob Gardiner | | 2026-09-28 | Square, n = 35 | 0.00443228 | +0.53% | Rob Gardiner | | 2026-09-25 | Convex, n = 31 | 0.00630967 | +3.46% | Alexandar Lackovic with help of Opus 5.5 | | 2026-09-25 | Convex, n = 33 | 0.00547013 | +3.21% | Alexandar Lackovic with help of Opus 5.5 | | 2026-09-23 | Triangle, n = 19 | 0.01348189 | +0.21% | Marc-Emmanuel Coupvent des Graviers | | 2026-09-23 | Triangle, n = 29 | 0.00612369 | +2.55% | Marc-Emmanuel Coupvent des Graviers |

The ten most recent improvements. New records are also published as an Atom feed.

Best known values

Truncated to 8 decimals; ▲ marks entries proven optimal.

| n | square | triangle | convex | | -- | ------------------------------------------------------------ | -------------------------------------------------------------- | ------------------------------------------------------------ | | 3 | 0.50000000 | 1.00000000 | 1.00000000 | | 4 | 0.50000000 | 0.33333333 | 0.50000000 | | 5 | 0.19245008 | 0.17157287 | 0.27639320 | | 6 | 0.12500000 | 0.12500000 | 0.16666666 | | 7 | 0.08385900 | 0.09722222 | 0.11111111 | | 8 | 0.07237642 | 0.06778921 | 0.08000013 | | 9 | 0.05487599 | 0.05484693 | 0.06406475 | | 10 | 0.04653741 | 0.04337674 | 0.05199307 | | 11 | 0.03703703 | 0.03652988 | 0.04255319 | | 12 | 0.03259885 | 0.03100478 | 0.03921568 | | 13 | 0.02701991 | 0.02655652 | 0.03093720 | | 14 | 0.02430397 | 0.02377577 | 0.02783558 | | 15 | 0.02121054 | 0.02109076 | 0.02456405 | | 16 | 0.02052785 | 0.01835554 | 0.02227287 | | 17 | 0.01726167 | 0.01624232 | 0.01905733 | | 18 | 0.01552605 | 0.01489434 | 0.01823889 | | 19 | 0.01394786 | 0.01348189 | 0.01593109 | | 20 | 0.01293819 | 0.01260939 | 0.01446420 | | 21 | 0.01147376 | 0.01139597 | 0.01319108 | | 22 | 0.01067285 | 0.01026612 | 0.01225496 | | 23 | 0.00975728 | 0.00926978 | 0.01108248 | | 24 | 0.00908900 | 0.00898515 | 0.01071264 | | 25 | 0.00823006 | 0.00780263 | 0.00931610 | | 26 | 0.00757759 | 0.00747156 | 0.00871478 | | 27 | 0.00710240 | 0.00702932 | 0.00802912 | | 28 | 0.00690052 | 0.00669434 | 0.00771884 | | 29 | 0.00627593 | 0.00612369 | 0.00728911 | | 30 | 0.00603852 | 0.00595740 | 0.00716018 | | 31 | 0.00583706 | 0.00516128 | 0.00630967 | | 32 | 0.00581090 | 0.00480075 | 0.00585071 | | 33 | 0.00507134 | 0.00472821 | 0.00547013 | | 34 | 0.00483489 | 0.00443091 | 0.00520621 | | 35 | 0.00443228 | 0.00403268 | 0.00477380 | | 36 | 0.00418488 | — | — |

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