Grassmann secants, identifiability, and linear systems of tensors

TL;DR

This paper establishes a criterion for the identifiability of irreducible non-degenerate varieties in projective space, linking it to secant varieties and Segre products, with implications for tensor decomposition.

Contribution

It provides a new criterion connecting $(k,s)$-identifiability of varieties to $s$-identifiability of Segre products, advancing understanding of tensor identifiability.

Findings

$(k,s)$-identifiability holds if and only if $s$-identifiability holds for the Segre product.

Non-defective secant varieties imply $(k,s)$-identifiability for certain pairs $(k,s)$.

The criterion applies to varieties with secant varieties not filling the ambient space.

Abstract

For any irreducible non-degenerate variety $X\subset \mathbb{P}^r$, we give a criterion for the $(k,s)$-identifiability of $X$. If $k\leq s-1 <r$, then the $(k,s)$-identifiability holds for $X$ if and only if the $s$-identifiability holds for the Segre product $Seg(\mathbb{P}^k\times X)$. Moreover, if the $s$-th secant variety of $X$ is not defective and it does not fill the ambient space, then we can produce a family of pairs $(k,s)$ for which the $(k,s)$-identifiability holds for $X$.