math.OCJun 2, 2026

Optimizing Explicit Unit-Distance Lower-Bound Certificates

Authors: Michael T. M. Emmerich

Organizations: Faculty of Information Technology, University of Jyväskylä, Finland.

Abstract

The 2026 disproof of Erdős's unit-distance conjecture and Sawin's quantitative refinement show that the maximum number u(n)u(n) of unit distances among nn planar points can exceed n1+εn^{1+\varepsilon} for a fixed positive ε\varepsilon. Sawin's explicit bound gives more than n1.014n^{1.014} unit distances for arbitrarily large nn and exposes integer parameters whose choice is not fully optimized. This report treats Sawin's parameter selection as a nonlinear integer optimization problem and develops an open-source Python optimization and verification pipeline for certificates involving prime sets TT and SQS_Q, integer multiplicities k(p)k(p), and a rationally encoded real parameter RR. After reproducing Sawin's certificate with δ=0.014114δ=0.014114\ldots, the pipeline yields improved certificates with the same TT. We develop a tailored integer evolution strategy achieving a certificate with δ=0.015263δ=0.015263\ldots and supporting the cautious statement u(n)>n1.0152u(n)>n^{1.0152} for arbitrarily large nn. For extended ramified prime ranges, the Emmerich--Cordella certificate obtained with the same framework reports u(n)>n1.031u(n)>n^{1.031} for #T=67\#T=67, illustrating the importance of enlarging TT. Very recent MathOverflow discussions, brought to the author's attention as of version~4, report further improvements, including certificates above δ>0.035δ>0.035 and beyond δ>0.036δ>0.036. Some of these improvements may rely not only on larger prime ranges but also on modified constraint systems and additional degrees of freedom that deviate from Sawin's original formulation. Beyond this application, the work illustrates how randomized optimization heuristics can improve, verify, and refine explicit certificates for combinatorial geometry through nonlinear integer optimization.

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