English

Unitary matrices associated with Butson-Hadamard matrices

Combinatorics 2020-02-25 v1

Abstract

We give an example of a BH(5; 5) matrix M satisfying that the eigenvalues of the unitary matrix 15M\frac{1}{\sqrt5}M are all primitive 10-th roots of unity and such that 15M3\frac{1}{5}M^3 is not a BH(5; 5) matrix. This example gives a negative answer to a conjecture proposed by R. Egan and P. O. Cathain.

Cite

@article{arxiv.2002.10355,
  title  = {Unitary matrices associated with Butson-Hadamard matrices},
  author = {Alberto Martín Méndez},
  journal= {arXiv preprint arXiv:2002.10355},
  year   = {2020}
}
R2 v1 2026-06-23T13:51:53.759Z