Decomposing tensors via rank-one approximations

Fuente: arXiv
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Main Authors: Ribot, Alvaro, Horobet, Emil, Seigal, Anna, Turatti, Ettore Teixeira
Format: Preprint
Published: 2024
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author Ribot, Alvaro
Horobet, Emil
Seigal, Anna
Turatti, Ettore Teixeira
author_facet Ribot, Alvaro
Horobet, Emil
Seigal, Anna
Turatti, Ettore Teixeira
contents Matrices can be decomposed via rank-one approximations: the best rank-one approximation is a singular vector pair, and the singular value decomposition writes a matrix as a sum of singular vector pairs. The singular vector tuples of a tensor are the critical points of its best rank-one approximation problem. In this paper, we study tensors that can be decomposed via successive rank-one approximations: compute a singular vector tuple, subtract it off, compute a singular vector tuple of the new deflated tensor, and repeat. The number of terms in such a decomposition may exceed the tensor rank. Moreover, the decomposition may depend on the order in which terms are subtracted. We show that the decomposition is valid independent of order if and only if all singular vectors in the process are orthogonal in at least two factors. We study the variety of such tensors. We lower bound its dimension, showing that it is significantly larger than the variety of odeco tensors.
format Preprint
id arxiv_https___arxiv_org_abs_2411_15935
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Decomposing tensors via rank-one approximations
Ribot, Alvaro
Horobet, Emil
Seigal, Anna
Turatti, Ettore Teixeira
Algebraic Geometry
Spectral Theory
14N07, 15A18, 15A69
Matrices can be decomposed via rank-one approximations: the best rank-one approximation is a singular vector pair, and the singular value decomposition writes a matrix as a sum of singular vector pairs. The singular vector tuples of a tensor are the critical points of its best rank-one approximation problem. In this paper, we study tensors that can be decomposed via successive rank-one approximations: compute a singular vector tuple, subtract it off, compute a singular vector tuple of the new deflated tensor, and repeat. The number of terms in such a decomposition may exceed the tensor rank. Moreover, the decomposition may depend on the order in which terms are subtracted. We show that the decomposition is valid independent of order if and only if all singular vectors in the process are orthogonal in at least two factors. We study the variety of such tensors. We lower bound its dimension, showing that it is significantly larger than the variety of odeco tensors.
title Decomposing tensors via rank-one approximations
topic Algebraic Geometry
Spectral Theory
14N07, 15A18, 15A69
url https://arxiv.org/abs/2411.15935