3 papers
math.CO2023
Three New Refined Arnold Families
Sen-Peng Eu, Louis Kao
The Springer numbers, introduced by Arnold, are generalizations of Euler numbers in the sense of Coxeter groups. They appear as the row sums of a double triangular array $(v_{n,k})…
math.CO2021
Sharp bounds of the -spectral radii of mixed trees
Yen-Jen Cheng, Louis Kao, Chih-Wen Weng
A mixed tree is a tree in which both directed arcs and undirected edges may exist. Let be a mixed tree with vertices and arcs, where an undirected edge is counted twice…
math.CO2020
The relation between Hamiltonian and -tough properties of the Cartesian product graphs
Louis Kao, Chih-wen Weng
The relation between Hamiltonicity and toughness of a graph is a long standing research problem. The paper studies the Hamiltonicity of the Cartesian product graph …