Gilmer–Kopparty local central limit theorem conjecture

Let HH be a fixed connected graph, let Gn,pG_{n,p} be the Erdős–Rényi random graph, and let XHX_H denote the number of copies of HH in Gn,pG_{n,p}. Define m(H)=max{e(J)/(v(J)1):JH, v(J)2}m(H)=\max\{e(J)/(v(J)-1):J\subseteq H,\ v(J)\ge 2\}. If p=p(n)p=p(n) satisfies pn1/m(H)p\gg n^{-1/m(H)} and n2(1p)1n^2(1-p)\gg 1, then XHX_H satisfies a local central limit theorem: writing μn=EXH\mu_n=\mathbb{E}X_H, σn2=Var(XH)\sigma_n^2=\operatorname{Var}(X_H), and ϕ(x)=(2π)1/2ex2/2\phi(x)=(2\pi)^{-1/2}e^{-x^2/2}, one has supkZσnPr(XH=k)ϕ((kμn)/σn)0\sup_{k\in\mathbb{Z}}\left|\sigma_n\Pr(X_H=k)-\phi\left((k-\mu_n)/\sigma_n\right)\right|\to 0 as nn\to\infty.

Progress summary

Partially solved

A new preprint settles the conjecture for every fixed clique in a broad sparse range, but the version for all connected graphs remains open.

Introduced by Justin Gilmer and Swastik Kopparty in 2016, the conjecture predicts a local normal approximation for copies of any fixed connected graph in a random graph when pn1/m(H)p\gg n^{-1/m(H)} and n2(1p)1n^2(1-p)\gg 1.

Known results

  • Röllin–Ross (2016): triangles for n1p=O(n1/2)n^{-1}\ll p=O(n^{-1/2}).
  • Gilmer–Kopparty (2016): triangles for fixed p(0,1)p\in(0,1).
  • Sah–Sawhney: every connected HH for constant pp.
  • Berkowitz (2018): fixed-clique counts for constant pp.

August 2026 sparse-clique theorem

Asaf Cohen Antonir, Ilay Hoshen, and Maksim Zhukovskii report a proof for every fixed clique H=KrH=K_r, r3r\ge 3, throughout n1/m(Kr)p12n^{-1/m(K_r)}\ll p\le \frac12. The arbitrary connected-graph conjecture remains open in the sparse regime.

Current status (as of August 2026): The conjecture is established for fixed cliques in the stated sparse range, and for broader graph classes in dense regimes, but remains open for arbitrary connected graphs in general sparse regimes.

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Primary source

arXiv

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