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The polynomial Freiman–Ruzsa conjecture

historic

· Additive combinatorics · resolved November 2023 · ~1 min read · difficulty 5/5

additive-combinatorics

The problem

A subset of \(\mathbb{F}_p^n\) with doubling constant \(K\) is covered by at most \(K^{O(1)}\) cosets of a subspace of size at most \(K^{O(1)}\) times the set. (Resolved 2023.)

History & significance

Freiman's theorem (integers, 1960s–70s) says small doubling forces approximate subgroup structure; Ruzsa extended the philosophy to general groups. Marton reformulated it over \(\mathbb{F}_2^n\) with polynomial bounds — the form that resisted for decades, with Sanders (2012) reaching quasipolynomial bounds. In November 2023 Gowers–Green–Manners–Tao proved the full polynomial conjecture, with an argument Tao estimated a computer search could in principle have found but humans did find first.