4 papers
On the Codegree graphs of finite groups
Jiyong Chen, Ni Du, Leyi Li
The codegree of an irreducible character of a finite group is defined as . The codegree graph of a finite group is the graph whose vertices are t…
On Bi-rotary Maps of Negative Prime Power Euler Characteristic
Jiyong Chen, Zhaochen Ding, Cai Heng Li
A map is bi-orientable if it admits an assignment of local orientations to its vertices such that for every edge, the local orientations at its two endpoints are opposite. Such an…
Non-solvable -arc-transitive covers of Petersen graphs
Jiyong Chen, Cai Heng Li, Ci Xuan Wu +1
We construct connected -arc-transitive covers of the Petersen graph with non-solvable transformation groups, solving the long-standing problem for the existence of such covers.
Coverings of Groups, Regular Dessins, and Surfaces
Jiyong Chen, Wenwen Fan, Cai Heng Li +1
A coset geometry representation of regular dessins is established, and employed to describe quotients and coverings of regular dessins and surfaces. A characterization is then give…