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The border rank of the $4 \times 4$ determinant tensor is twelve

Algebraic Geometry 2025-10-14 v1 Commutative Algebra

Abstract

We show that the border rank of the 4×44 \times 4 determinant tensor is at least 1212 over C\mathbb{C}, using the fixed ideal theorem introduced by Buczy\'nska-Buczy\'nski and the method by Conner-Harper-Landsberg. Together with the known upper bound, this implies that the border rank is exactly 1212.

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Cite

@article{arxiv.2510.11051,
  title  = {The border rank of the $4 \times 4$ determinant tensor is twelve},
  author = {Jong In Han and Jeong-Hoon Ju and Yeongrak Kim},
  journal= {arXiv preprint arXiv:2510.11051},
  year   = {2025}
}

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