4 papers
math.CO2026
The diameter of recoloring graphs under a maximum average degree bound
Ruilin Zheng, Junying Lu
For a graph , we write for its maximum average degree and for its diameter. Let be the graph whose vertices are the proper colorings…
math.CO2026
Two-block cycles and chromatic number of Hamiltonian digraphs
Ruilin Zheng, Junying Lu, Xiaolin Wang +1
Let and be positive integers. The family consists of all digraphs obtained from two internally vertex-disjoint directed paths of lengths at least and $\e…
math.CO2023
Connectedness of friends-and-strangers graphs of complete bipartite graphs and others
Lanchao Wang, Junying Lu, Yaojun Chen
Let and be any two graphs of order . The friends-and-strangers graph of and is a graph with vertex set consisting of all bijections $σ:V(X) \m…
math.CO2022
Spectral radius of graphs forbidden or
Junying Lu, Lu Lu, Yongtao Li
Let be the graph obtained from a cycle by adding a new vertex connecting two adjacent vertices in . In this note, we obtain the graph maximizing th…