Notes on Kozma and Nitzan's proof of $θ(p_c)=0$
Kozma and Nitzan reduced θ(p_c)=0 for Bernoulli percolation on Z^d (d≥3) to a conjectured correlation inequality. An AI recently proved that inequality, but the result came as about 100,000 lines of Lean with poorly written manuscripts that were hard for probabilists to check.
The authors reconstruct a human-written proof from the AI's ideas, with their own notation. They use nested inductions on the sets A and B, linear projection operators π_{A,B}, covariance operators κ, and Harris's inequality with a Gibbs-type argument. They skip the 'horizontal term' and its long estimate.
They obtain a self-contained proof of the Kozma–Nitzan conjectures that is roughly half the length of the original. Combined with Kozma and Nitzan's work, this yields θ(p_c)=0. The underlying result has Lean 4/Mathlib formalizations, which are cited.
