Jun Ge

activity

20182021

collaborators

Showing math.COShow all

4 papers · 1 filter

math.CO2021

Some new results on bar visibility of digraphs

Yuanrui Feng, Jun Ge, Douglas B. West +1

Visibility representation of digraphs was introduced by Axenovich, Beveridge, Hutch\-inson, and West (\emph{SIAM J. Discrete Math.} {\bf 27}(3) (2013) 1429--1449) as a natural gene…

math.CO2021

Express the number of spanning trees in term of degrees

Fengming Dong, Jun Ge, Zhangdong Ouyang

It is well-known that the number of spanning trees, denoted by $τ (G)$ , in a connected multi-graph $G$ can be calculated by the Matrix-Tree theorem and Tutte's deletion-contraction…

math.CO2020

Upper bounds on the signed edge domination number of a graph

Fengming Dong, Jun Ge, Yan Yang

A signed edge domination function (or SEDF) of a simple graph $G = (V, E)$ is a function $f : E \to {1, - 1}$ such that $\sum_{e^{'} \in N [e]} f (e^{'}) \geq 1$ holds for each edge $e\in E…

math.CO2018

Proving a conjecture on chromatic polynomials by counting the number of acyclic orientations

Fengming Dong, Jun Ge, Helin Gong +3

The chromatic polynomial $P (G, x)$ of a graph $G$ of order $n$ can be expressed as $i = 1 \sum n (- 1)^{n - i} a_{i} x^{i}$ , where $a_{i}$ is interpreted as the number of broken-cycle…