Structured witness: A = B ⊕ 35·E with E=[0, 1], B a nested parabola set in Z/35 × Z built from the chain [7, 5] (outermost first): y = Σ_i w_i·y_i(u_i) where y_i is a compact representative of λ_i·u_i² mod p_i and w_i = p_1⋯p_{i-1}, placed in Z/7315 = Z/(35·209) by CRT. Mixed-radix encoding keeps the y-span at Σ w_i·s_i + g·max E; M below the span-rule bound 4·span+1 is obtained by checking wrap-around solutions exactly and greedily dropping a hitting set (0 dropped). Generalizes witness#44533 / witness#54659; same method at every modulus g·M in this range.
David Renshaw · 2026-09-03 20:09:16 UTC