Orbit classification of determinant-tensor decompositions

Investigate the orbit of tensor rank decompositions of the \(n \times n\) determinant tensor \(\operatorname{det}_n\) under the diagonal action of \(\operatorname{SL}_n\) for general \(n\), including whether known decompositions belong to the same orbit.

Background

The n×nn \times n determinant tensor is invariant under the diagonal action of SL⁡n\operatorname{SL}_n, so applying this group action to any tensor rank decomposition produces another decomposition of the same tensor. The paper verifies that two known decompositions lie in the same SL⁡n\operatorname{SL}_n-orbit for n=3n=3 and n=4n=4. A general description or classification of these orbits for arbitrary nn remains unresolved.

References

In Remark \ref{remark:comparison with another tensor decomposition}, we verified that the two known tensor rank decompositions of $\operatorname{det}_n$ are in the same orbit under the $\operatorname{SL}_n$-action for $n=3,4$. We leave the investigation of this orbit for general $n$ as a problem for future work.

— Improved Upper Bounds for the Rank of the Determinant Tensor via Glynn's Formula  (2610.18394 - Ju et al., 13 Oct 2026) in Section 5, Further directions