16 papers · 1 filter
New upper bound for the Ramsey number of odd cycles
Ting Huang, Jiabao Yang, Yaojun Chen
The \emph{-color Ramsey number} is the least integer such that any -edge-coloring of a complete graph has a monochromatic odd cycle …
Erdős--Ko--Rado theorems in -norm for three finite spaces
Qian Bao, Yaojun Chen, Yanbo Zhang
Let be a -uniform hypergraph. The famous Erdős--Ko--Rado (1961) theorem determines the maximum size and extremal structure for being -intersecting…
On monochromatic path covers conjecture of Erdős--Gyárfás
Hangdi Chen, Yaojun Chen
Erdős and Gyárfás conjectured in 1995 that, in every red--blue edge-coloring of a complete graph , the vertex set can be covered by at most monochromatic paths, all…
A note on tree-cycle Ramsey numbers
Ting Huang, Yanbo Zhang, Yaojun Chen
Let denote the Ramsey number of a tree on vertices versus a cycle of length . Burr, Erdős, Faudree, Rousseau, and Schelp (1982) asked for the least…
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…
On regular homogeneously traceable nonhamiltonian graphs
Hangdi Chen, Yaojun Chen
A graph is homogeneously traceable if each vertex is an endpoint of a Hamiltonian path. Chartrand, Gould, and Kapoor (1979) proved irregular homogeneously traceable nonhamiltonian…