2 citations · 4 across the 6 of their papers we have counts for
15 papers · 1 filter
Maximal digraphs whose Hermitian spectral radius is at most
Alexander L. Gavrilyuk, Akihiro Munemasa
We classify maximal digraphs whose Hermitian spectral radius is at most .
Maximality of Seidel matrices and switching roots of graphs
Meng-Yue Cao, Jack H. Koolen, Akihiro Munemasa +1
In this paper, we discuss maximality of Seidel matrices with a fixed largest eigenvalue. We present a classification of maximal Seidel matrices of largest eigenvalue , which giv…
Bordered complex Hadamard matrices and strongly regular graphs
Takuya Ikuta, Akihiro Munemasa
We consider bordered complex Hadamard matrices whose core is contained in the Bose-Mesner algebra of a strongly regular graph. Examples include a complex Hadamard matrix whose core…
Signed analogue of line graphs and their smallest eigenvalues
Alexander L. Gavrilyuk, Akihiro Munemasa, Yoshio Sano +1
In this paper, we show that every connected signed graph with smallest eigenvalue strictly greater than and large enough minimum degree is switching equivalent to a complete g…
Ternary codes, biplanes, and the nonexistence of some quasi-symmetric and quasi-3 designs
Akihiro Munemasa, Vladimir D. Tonchev
The dual codes of the ternary linear codes of the residual designs of biplanes on 56 points are used to prove the nonexistence of quasi-symmetric 2- and 2- d…
A note on Assmus--Mattson type theorems
Tsuyoshi Miezaki, Akihiro Munemasa, Hiroyuki Nakasora
In the present paper, we give Assmus--Mattson type theorems for codes and lattices. We show that a binary doubly even self-dual code of length 24m with minimum weight 4m provides a…