English

Uniqueness of Butson Hadamard matrices of small degrees

Combinatorics 2014-02-28 v1

Abstract

For positive integers mm and nn, we denote by BH(m,n)\mathrm{BH}(m,n) the set of all HMn×n(C)H\in M_{n\times n}(\mathbb{C}) such that HH=nInHH^\ast=nI_n and each entry of HH is an mm-th root of unity where HH^\ast is the adjoint matrix of HH and InI_n is the identity matrix. For H1,H2BH(m,n)H_1,H_2\in \mathrm{BH}(m,n) we say that H1H_1 is \textit{equivalent} to H2H_2 if H1=PH2QH_1=PH_2 Q for some monomial matrices P,QP, Q whose nonzero entries are mm-th roots of unity. In this paper we classify BH(17,17)\mathrm{BH}(17,17) up to equivalence by computer search.

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Cite

@article{arxiv.1402.6807,
  title  = {Uniqueness of Butson Hadamard matrices of small degrees},
  author = {Kyoung-Tark Kim and Hirasaka Mitsugu and Yoshihiro Mizoguchi},
  journal= {arXiv preprint arXiv:1402.6807},
  year   = {2014}
}

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9 pages