# A Bernstein type inequality for sums of selections from three dimensional arrays

## TL;DR

This paper establishes Bernstein-type concentration inequalities for sums of selected entries from three-dimensional arrays, extending classical results to more complex, higher-dimensional random permutation-based statistics.

## Contribution

The paper introduces Bernstein inequalities for three-dimensional array sums involving permutations, generalizing previous two-dimensional results.

## Key findings

- Derived Bernstein inequalities for sums T1 and T2.
- Extended concentration results from 2D to 3D array settings.
- Provides tools for analyzing permutation-based sums in higher dimensions.

## Abstract

We consider the three dimensional array $\mathcal{A} = \{a_{i,j,k}\}_{1\le i,j,k \le n}$, with $a_{i,j,k} \in [0,1]$, and the two random statistics $T_{1}:= \sum_{i=1}^n \sum_{j=1}^n a_{i,j,\sigma(i)}$ and $T_{2}:= \sum_{i=1}^{n} a_{i,\sigma(i),\pi(i)}$, where $\sigma$ and $\pi$ are chosen independently from the set of permutations of $\{1,2,\ldots,n \}.$ These can be viewed as natural three dimensional generalizations of the statistic $T_{3}=\sum_{i=1}^{n} a_{i,\sigma(i)}$, considered by Hoeffding \cite{Hoe51}. Here we give Bernstein type concentration inequalities for $T_{1}$ and $T_{2}$ by extending the argument for concentration of $T_{3}$ by Chatterjee \cite{Cha05}.