Faster search for tensor decomposition over finite fields

TL;DR

This paper introduces faster algorithms for determining the tensor rank over finite fields, significantly improving computational efficiency for tensors of various dimensions.

Contribution

The authors develop new algorithms with improved time complexity for tensor rank determination over finite fields, extending previous methods and optimizing for specific tensor dimensions.

Findings

Algorithms run in polynomial space.

Significant speedup over previous methods.

Effective for tensors with large dimensions.

Abstract

We present an $O^*(|\mathbb{F}|^{\min\left\{R,\ \sum_{d\ge 2} n_d\right\} + (R-n_0)(\sum_{d\ne 0} n_d)})$-time algorithm for determining whether the rank of a concise tensor $T\in\mathbb{F}^{n_0\times\dots\times n_{D-1}}$ is $\le R$, assuming $n_0\ge\dots\ge n_{D-1}$ and $R\ge n_0$. For 3-dimensional tensors, we have a second algorithm running in $O^*(|\mathbb{F}|^{n_0+n_2 + (R-n_0+1-r_*)(n_1+n_2)+r_*^2})$ time, where $r_*:=\left\lfloor\frac{R}{n_0}\right\rfloor+1$. Both algorithms use polynomial space and improve on our previous work, which achieved running time $O^*(|\mathbb{F}|^{n_0+(R-n_0)(\sum_d n_d)})$.