Exact Cohn–Elkies d=2 certificate

Replay:

/tmp/ce-venv/bin/python verify.py

or ./run_all.sh (rebuilds the certificate, then verifies).

certs/ce_d2_m5.json is the exact auxiliary function: radial profile polynomials F(t), hatF(t) in t = 2π|x|², times the Gaussian exp(-π|x|²). Theorem 3.2 of Cohn–Elkies 2003 then gives

center density ≤ R/(8π),   R = 3627599/500000 = 7.255198.

That meets Cohn–Elkies Table 3 (0.28868) and is strictly below the printed Table 4 value 2πr² = 7.25520. It is not a magic function: the hexagonal target is 4π/√3 ≈ 7.2551974569.