Ten improved spherical codes in dimensions 11 to 17
Listed in Henry Cohn’s table of spherical codes, each row credited Antoine Olivier, 2026.
Submitted 19 October 2026. Credit read in the table on 20 October 2026.
A spherical code is a set of N points on the unit sphere in dimension d; the goal is to keep the largest cosine between any two points as small as possible. For these ten (d, N) pairs, the new codes improve on the table values read on 19 October 2026, before submission.
New maximum cosine (certified upper bound, 12 decimals), table value before submission, and improvement (rounded; bar on a log scale from 10−10 to 10−4).
| d | N | New max cosine | Before | Improvement |
|---|---|---|---|---|
| 11 | 82 | 0.263018342364 | 0.263018878676 | 5.4e-7 |
| 12 | 66 | 0.214718112242 | 0.214727052210 | 8.9e-6 |
| 12 | 92 | 0.258276397340 | 0.258374597677 | 9.8e-5 |
| 13 | 72 | 0.205422579377 | 0.205422584282 | 4.9e-9 |
| 13 | 95 | 0.244097860377 | 0.244179109624 | 8.1e-5 |
| 14 | 76 | 0.189882980940 | 0.189882981278 | 3.4e-10 |
| 14 | 80 | 0.195566522972 | 0.195566565102 | 4.2e-8 |
| 15 | 75 | 0.168255719871 | 0.168258837686 | 3.1e-6 |
| 17 | 83 | 0.149970576801 | 0.149982620206 | 1.2e-5 |
| 17 | 84 | 0.149993159821 | 0.149995256047 | 2.1e-6 |
Local polishing by sequential linear programming. Eight codes start from entries the table marked as needing more optimization; (12, 92) and (13, 95) start from the codes with one more point by Ilmari Vahteristo and Luke Granto, minus one point.
Coordinates were scaled by 252 and rounded to integers. Two independent programs (Python and PARI/GP) then checked in exact integer arithmetic that the largest cosine, which does not depend on scale, is at most the value shown. These are computational records, not proofs of optimality.
Computed in October 2026 with Claude Opus 5.5 (Anthropic) working as a coding agent in Claude Code under my direction. I take responsibility for the submission.