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The Hanson-Wright Inequality for Random Tensors

2021/06/24 by Bamberger, Stefan, Krahmer, Felix, Ward, Rachel
#FOS: Mathematics #Probability (math.PR)

paper · doi:10.48550/arxiv.2106.13345

Abstract

We provide moment bounds for expressions of the type (X(1) ⊗ … ⊗ X(d))T A (X(1) ⊗ … ⊗ X(d)) where ⊗ denotes the Kronecker product and X(1), …, X(d) are random vectors with independent, mean 0, variance 1, subgaussian entries. The bounds are tight up to constants depending on d for the case of Gaussian random vectors. Our proof also provides a decoupling inequality for expressions of this type. Using these bounds, we obtain new, improved concentration inequalities for expressions of the form ‖B (X(1) ⊗ … ⊗ X(d))‖2.

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