problems / fekete-s2

Also in this folder: compute/

Attack log — elliptic Fekete points on S2S^2

2026-08-19 — start

Published records fetched tonight

Sources actually opened (arXiv HTML/PDF or author PDF), not forum posts:

No later accepted table with a lower Emin⁡E_{\min} for any modest NN was found tonight. The number to beat for 4≤N≤654\le N\le 65 is the first (global) entry of Ridgway–Cheviakov Table 3, refined by Rathbun–Ridgway to many more digits.

Plan

  1. Independent verifier: project to S2S^2, print EE. Sanity: tetrahedron, octahedron, icosahedron.
  2. Replay Table 3 for several NN by regenerating known optima and by multi-start Riemannian descent with deterministic seeds.
  3. Search at NN with slack: 7, 8, 9, 10, 14, 19, 24, 32, 33, 46, 48. N=33N=33 is the paper's own hard case (saddle first, then 10610^6 iterations).
  4. A printed 8-decimal that we undercut only in the last digit is rounding, not a beat. A new configuration whose EE is below the printed global by more than 10−710^{-7} (Rathbun's comparison tolerance) would be a candidate.

Files

2026-08-19 — verifier sanity

compute/known.py + energy.py:

NN config EE Table 3
4 tetrahedron 3log⁡(3/8)3\log(3/8) −2.942487759035-2.942487759035 −2.9424878-2.9424878
5 1:3:1 −4log⁡2−1.5log⁡3-4\log 2-1.5\log 3 −4.420507155242-4.420507155242 −4.4205072-4.4205072
6 octahedron −9log⁡2-9\log 2 −6.238324625040-6.238324625040 −6.2383246-6.2383246
7 1:5:1 −8.182477864445-8.182477864445 −8.1824779-8.1824779
12 icosahedron −21.606145230445-21.606145230445 −21.6061452-21.6061452

Beltrán–Lizarte's printed Elog⁡=−16.3649557E_{\log}=-16.3649557 for N=7N=7 is exactly 2E2E (their ∑i≠j\sum_{i\neq j}). Convention check, not a beat.

2026-08-19 — full Table 3 replay from published coordinates

Zenodo 5595366 log.3.N.80 parsed and run through energy.py. Every N=2N=2–6565 matches the file ener= to ∼10−13\sim 10^{-13} (N=34 has no ener= line; we still recompute E=−142.3758522709E=-142.3758522709 vs Table 3 −142.3758523-142.3758523). Every Table 3 global matches to the printed 8 decimals (∣Δ∣<5×10−8|\Delta|<5\times 10^{-8}, the rounding of the last digit). Table: compute/replay_rathbun.json.

This is a replay of the published record, not a dent.

2026-08-19 — search at slack NN

Deterministic seeds (Fibonacci, RSZ spiral, square-antiprism heights for N=8N=8, 32 RNG seeds with base 4102, plus Rathbun + four kicks). Riemannian Armijo descent. Independent verifier on stored points.

NN our EE Table 3 Δ\Delta from-scratch?
7 −8.182477864445-8.182477864445 −8.1824779-8.1824779 +3.6⋅10−8+3.6\cdot 10^{-8} yes (1:5:1)
8 −10.428017781460-10.428017781460 −10.4280178-10.4280178 +1.9⋅10−8+1.9\cdot 10^{-8} yes (antiprism)
9 −12.887752725759-12.887752725759 −12.8877527-12.8877527 −2.6⋅10−8-2.6\cdot 10^{-8} rounding only
10 −15.563123389022-15.563123389022 −15.5631234-15.5631234 +1.1⋅10−8+1.1\cdot 10^{-8} yes
14 −28.407813009242-28.407813009242 −28.407813-28.407813 −9⋅10−9-9\cdot 10^{-9} rounding only
19 −49.199891565787-49.199891565787 −49.1998916-49.1998916 +3.4⋅10−8+3.4\cdot 10^{-8} rng within 10−710^{-7}
24 −75.213984788629-75.213984788629 −75.2139848-75.2139848 +1.1⋅10−8+1.1\cdot 10^{-8} yes (all seeds)
32 −127.378867614780-127.378867614780 −127.3788676-127.3788676 −1.5⋅10−8-1.5\cdot 10^{-8} yes (all seeds)
33 −134.747820824333-134.747820824333 −134.7478208-134.7478208 −2.4⋅10−8-2.4\cdot 10^{-8} no; rng ∼10−6\sim 10^{-6} high
46 −249.455847900857-249.455847900857 −249.4558479-249.4558479 −9⋅10−10-9\cdot 10^{-10} yes (spiral, some rng)
48 −270.117949959283-270.117949959283 −270.11795-270.11795 +4.1⋅10−8+4.1\cdot 10^{-8} yes (all seeds)

No Δ<−10−7\Delta < -10^{-7}. The tiny negatives are extra digits of the same 8-decimal print. Not a beat.

N=46N=46 independently recovers the 2018 new global from spiral and several rng starts. Many rng land on the published local −249.454650-249.454650, which is Table 3's second line. Fibonacci stalls at −249.44978-249.44978, a still-worse basin. That is the residue: the landscape has the old and new globals close together, and we found both, not a third.

N=33N=33 is the paper's saddle/global struggle. Kicks from the published point stay at the global; 32 random starts do not reach it within 10−610^{-6}. We did not improve it.

Stop

No certified beat. Outcome (B): replay + residue. Smale 7 not claimed.