Forbidden Sidon subsets of perfect difference sets, featuring a human-assisted proof
- 1Independent Researcher
- 2Department of Mathematics, The Ohio State University
- 3Translational Data Analytics Institute, The Ohio State University
Abstract
We resolve a $1,000 Erdős prize problem, complete with formal verification generated by a large language model. In over a dozen papers, beginning in 1976 and spanning two decades, Paul Erdős repeatedly posed one of his "favorite" conjectures: every finite Sidon set can be extended to a finite perfect difference set. We establish that {1, 2, 4, 8, 13} is a counterexample to this conjecture. During the preparation of this paper, we found that although this problem was presumed to be open for half a century, Marshall Hall, Jr. published a different counterexample three decades before Erdős first posed the problem. With a healthy skepticism of this apparent oversight, and out of an abundance of caution, we used ChatGPT to vibe prove both Hall's and our counterexamples in Lean.
Related
- Finding an almost perfect matching in a hypergraph avoiding forbidden submatchings
- A Uniform Product-Difference Theorem for Dense Subsets of ℤ2
- Optimal entanglement-assisted source coding under a balanced-difference promise
- Càdlàg Solutions to Backward Stochastic Dynamics featuring Oblique Subgradients and driven by Martingale Noise
- Inertial Primal-Dual Dynamics Methods Featuring Implicit Hessian-Driven Damping for Convex Optimization Problems in Continuous and Discrete Time
BibTeX
@article{alexeev2026forbidden,
title = {{Forbidden Sidon subsets of perfect difference sets, featuring a human-assisted proof}},
author = {Boris Alexeev and Dustin G. Mixon},
journal = {Proceedings of the National Academy of Sciences},
year = {2026},
month = may,
doi = {10.1073/pnas.2531760123},
url = {https://doi.org/10.1073/pnas.2531760123},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Forbidden Sidon subsets of perfect difference sets, featuring a human-assisted proof
AU - Boris Alexeev
AU - Dustin G. Mixon
PY - 2026
DA - 2026/05/22
JO - Proceedings of the National Academy of Sciences
DO - 10.1073/pnas.2531760123
UR - https://doi.org/10.1073/pnas.2531760123
AB - We resolve a $1,000 Erdős prize problem, complete with formal verification generated by a large language model. In over a dozen papers, beginning in 1976 and spanning two decades, Paul Erdős repeatedly posed one of his "favorite" conjectures: every finite Sidon set can be extended to a finite perfect difference set. We establish that {1, 2, 4, 8, 13} is a counterexample to this conjecture. During the preparation of this paper, we found that although this problem was presumed to be open for half a century, Marshall Hall, Jr. published a different counterexample three decades before Erdős first posed the problem. With a healthy skepticism of this apparent oversight, and out of an abundance of caution, we used ChatGPT to vibe prove both Hall's and our counterexamples in Lean.
SN - 0027-8424
SN - 1091-6490
ER -