Optimal Matching Problem on the Boolean Cube
Shi Feng
TL;DR
This work characterizes the expected Wasserstein-1 distance between the empirical distribution on the Boolean cube $\mathbb{B}=\oldsymbol{-1,1\boldsymbol}$ and the uniform measure, across multiple regimes of the sample size $N$. Combining Fourier analysis on the Boolean cube with large-deviation techniques, it derives precise upper and lower bounds for $\mathbb{E}[\mathsf{W}_1(\mu_N,\mu)]$ in regimes ranging from small to very large $N$ (including $N$ proportional to $2^n$ and $N=e^{\lambda n}$). The paper also establishes general properties of the matching problem, including a best-guess measure, monotonicity in $N$, and concentration/variance bounds, and demonstrates that the uniform measure often minimizes expected matching distance under Haar-invariant group actions. These results provide a detailed, regime-specific understanding of optimal matching on the Boolean cube and illuminate contrasts with continuous spaces, with potential implications for high-dimensional discrete sampling and related combinatorial optimization problems.
Abstract
We establish upper and lower bounds for the expected Wasserstein distance between the random empirical measure and the uniform measure on the Boolean cube. Our analysis leverages techniques from Fourier analysis, following the framework introduced in \cite{bobkov2021simple}, as well as methods from large deviations theory.
