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math.CO2024
Spectral integral variation of signed graphs
Jungho Ahn, Cheolwon Heo, Sunyo Moon
We characterize when the spectral variation of the signed Laplacian matrices is integral after a new edge is added to a signed graph. As an application, for every fixed signed comp…
math.CO2023
Laplacian eigenvalue distribution for unicyclic graphs
Sunyo Moon, Seungkook Park
Let be a unicyclic graph. In this paper, we provide an upper bound for the number of Laplacian eigenvalues of within the interval in terms of the diameter and the g…
math.CO2023
Bounds for the geometric-arithmetic index of unicyclic graphs
Sunyo Moon, Seungkook Park
We present lower and upper bounds for the geometric-arithmetic index of unicyclic graphs and provide extremal graphs for the corresponding bounds.
math.CO2022
The rank of the walk matrix of the extended Dynkin graph
Sunyo Moon, Seungkook Park
In this paper, we provide an explicit formula for the rank of the walk matrix of the extended Dynkin graph .