Sharp spectral norm concentration of sparse random tensors

arXiv:2609.20520 · math.PR, math.CO, math.ST, stat.ML, stat.TH · Submitted 2026-09-17 · Read on arXiv

math.PR, math.CO, math.ST, stat.ML, stat.TH

Submitted: 2026-09-17

Updated: 2026-09-17

Comments: 18 pages

License: http://creativecommons.org/licenses/by/4.0/

The gist: We prove a sharp concentration inequality for the spectral norm of sparse random tensors with independent Bernoulli entries.

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Abstract

We prove a sharp concentration inequality for the spectral norm of sparse random tensors with independent Bernoulli entries. Let T be an order- k tensor of dimension n times times n with independent Bernoulli (p) entries, where k is fixed. For any c,r>0, we show that T- E T C k,r,c sqrt np with probability at least 1-n-r whenever np c n. We extend this bound to inhomogeneous Bernoulli sampling with deterministic entrywise weights. This removes the logarithmic factor in the work of Zhou and Zhu (2021). The proof follows the Kahn--Szemerédi light--heavy decomposition with a refined estimate on the heavy tuple part. We also obtain a log-free second eigenvalue bound for the random hypergraph model of Friedman and Wigderson (1995).

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