English

A simple proof of local universality for roots of Kac polynomials

Probability 2026-04-23 v2 Complex Variables

Abstract

Let fnf_n be a random polynomial of degree nn with i.i.d. mean-zero and finite variance random coefficients. It is well known that the roots of fnf_n cluster uniformly around the unit circle as nn grows large. We give a simple and self-contained proof of local universality for the correlation functions of the roots at the microscopic scale 1/n1/n around a fixed point on the circle. While previous proofs of local universality were focused on studying the logarithmic potential of fnf_n, we instead directly compare the scaled random polynomial to a limiting Gaussian analytic function, and establish convergence of correlations via a soft argument, using only basic complex analysis and an anti-concentration bound of Esseen.

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Cite

@article{arxiv.2511.21455,
  title  = {A simple proof of local universality for roots of Kac polynomials},
  author = {Marcus Michelen and Oren Yakir},
  journal= {arXiv preprint arXiv:2511.21455},
  year   = {2026}
}

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10 pages