Information-Theoretic Guarantees for Recovering Low-Rank Tensors from Symmetric Rank-One Measurements
Eren C. Kızıldağ
TL;DR
This work derives information-theoretic guarantees for exactly recovering a low symmetric-rank order-$\ell$ tensor from symmetric rank-one measurements with i.i.d. log-concave entries. The authors prove a near-optimal sample complexity of $N=\Theta(dr)$ for exact recovery via a rank-minimization program, and complement it with a Fano-based lower bound showing that $N=\tilde{\Omega}(dr^{0.98})$ is necessary up to polylog factors, underscoring the efficiency of the low-rank approach. They connect these results to learning two-layer polynomial networks, demonstrate that ERM over unstructured tensors can require exponentially more samples, and develop a suite of tools—covering numbers, Carbery–Wright anti-concentration, and orthogonal-polynomial expansions—to handle symmetric rank-one measurements under log-concave distributions. The paper highlights the potential for information-theoretic benchmarks to guide the design of tractable algorithms and deepens understanding of sample complexity in structured tensor recovery and polynomial-network settings.
Abstract
In this paper, we investigate the sample complexity of recovering tensors with low symmetric rank from symmetric rank-one measurements. This setting is particularly motivated by the study of higher-order interactions and the analysis of two-layer neural networks with polynomial activations (polynomial networks). Using a covering numbers argument, we analyze the performance of the symmetric rank minimization program and establish near-optimal sample complexity bounds when the underlying distribution is log-concave. Our measurement model involves random symmetric rank-one tensors, which lead to involved probability calculations. To address these challenges, we employ the Carbery-Wright inequality, a powerful tool for studying anti-concentration properties of random polynomials, and leverage orthogonal polynomials. Additionally, we provide a sample complexity lower bound based on Fano's inequality, and discuss broader implications of our results for two-layer polynomial networks.
