Google Research

On the Sample Complexity of Privately Learning Axis-Aligned Rectangles

NeurIPS 2021

Abstract

We revisit the fundamental problem of learning Axis-Aligned-Rectangles over a finite grid $X^d$ with differential privacy. Existing results show that the sample complexity of this problem is at most $\min\left\{ d\log|X| , d^{1.5}\left(\log^|X| \right)^{1.5}\right\}$. That is, existing constructions either require sample complexity that grows linearly with $\log|X|$, or else it grows super linearly with the dimension $d$. We present a novel algorithm that reduces the sample complexity to only $\tildeO{d \left(\log^|X|\right)^{1.5}}$, attaining a dimensionality optimal dependency without requiring the sample complexity to grow with $\log|X|$. The technique used in order to attain this improvement involves the deletion of ``exposed'' data-points on the go, in a fashion designed to avoid the cost of the adaptive composition theorems. The core of this technique may be of individual interest, introducing a new method for constructing statistically-efficient private algorithms.

Learn more about how we do research

We maintain a portfolio of research projects, providing individuals and teams the freedom to emphasize specific types of work