Yen-Jen Cheng

collaborators

4 papers

math.CO2022

Statistics of Partial Permutations via Catalan matrices

Yen-Jen Cheng, Sen-Peng Eu, Hsiang-Chun Hsu

A generalized Catalan matrix $(a_{n, k})_{n, k \geq 0}$ is generated by two seed sequences $s = (s_{0}, s_{1}, \dots)$ and $t = (t_{1}, t_{2}, \dots)$ together with a recurrence re…

math.CO2022

On Signed Multiplicities of Schur Expansions Surrounding Petrie Symmetric Functions

Yen-Jen Cheng, Meng-Chien Chou, Sen-Peng Eu +2

For $k \geq 1$ , the homogeneous symmetric functions $G (k, m)$ of degree $m$ defined by $\sum_{m \geq 0} G (k, m) z^{m} = \prod_{i \geq 1} (1 + x_{i} z + x_{i}^{2} z^{2} + \dots + x_{i}^{k - 1} z^{k - 1})$ are…

math.CO2021

Sharp bounds of the $A_{α}$ -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 $T$ be a mixed tree with $n$ vertices and $m$ arcs, where an undirected edge is counted twice…

math.CO2021

Counterexamples of the Bhattacharya-Friedland-Peled conjecture

Yen-Jen Cheng, Chia-An Liu, Chih-wen Weng

The Brauldi-Hoffman conjecture, proved by Rowlinson in 1988, characterized the graph with maximal spectral radius among all simple graphs with prescribed number of edges. In 2008,…

Statistics of Partial Permutations via Catalan matrices

On Signed Multiplicities of Schur Expansions Surrounding Petrie Symmetric Functions

Sharp bounds of the Aα​-spectral radii of mixed trees

Counterexamples of the Bhattacharya-Friedland-Peled conjecture

Sharp bounds of the $A_{α}$ -spectral radii of mixed trees