M. Hirasaka

activity

20102021

most citedUpper bounds on cyclotomic numbers

8 citations · 13 across the 11 of their papers we have counts for

collaborators

Showing 2014Show all

2 papers · 1 filter

math.CO2014

Isomorphism classes of association schemes induced by Hadamard matrices

Mitsugu Hirasaka, Kijung Kim, Hyonju Yu

Every Hadamard matrix $H$ of order $n > 1$ induces a graph with $4 n$ vertices, called the Hadamard graph $Γ (H)$ of $H$ . Since $Γ (H)$ is a distance-regular graph with diameter $4$ ,…

math.CO2014

Uniqueness of Butson Hadamard matrices of small degrees

Kyoung-Tark Kim, Hirasaka Mitsugu, Yoshihiro Mizoguchi

For positive integers $m$ and $n$ , we denote by $BH (m, n)$ the set of all $H \in M_{n \times n} (C)$ such that $H H^{*} = n I_{n}$ and each entry of $H$ is an $m$ -th root…