English

A sign pattern with non-zero elements on the diagonal whose minimal rank realizations are not diagonalizable over the complex numbers

Combinatorics 2020-02-04 v1

Abstract

The rank of the 9×99\times 9 matrix (110010000110000000001110000001100000000010101000001100000001100000000011000000011) \left( \begin{array}{cccc|c|cccc} 1&1&0&0&1&0&0&0&0\\ 1&1&0&0&0&0&0&0&0\\ 0&0&1&1&1&0&0&0&0\\ 0&0&1&1&0&0&0&0&0\\\hline 0&0&0&0&1&0&1&0&1\\\hline 0&0&0&0&0&1&1&0&0\\ 0&0&0&0&0&1&1&0&0\\ 0&0&0&0&0&0&0&1&1\\ 0&0&0&0&0&0&0&1&1 \end{array} \right) is 66. If we replace the ones by arbitrary non-zero numbers, we get a matrix BB with rankB6\operatorname{rank} B\geqslant6, and if rankB=6\operatorname{rank} B=6, the 6×66\times 6 principal minors of BB vanish.

Keywords

Cite

@article{arxiv.2002.00912,
  title  = {A sign pattern with non-zero elements on the diagonal whose minimal rank realizations are not diagonalizable over the complex numbers},
  author = {Yaroslav Shitov},
  journal= {arXiv preprint arXiv:2002.00912},
  year   = {2020}
}

Comments

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R2 v1 2026-06-23T13:29:38.239Z