5 papers
Extremal eigenvalues of sample covariance matrices with general population
Jinwoong Kwak, Ji Oon Lee, Jaewhi Park
We consider the eigenvalues of sample covariance matrices of the form . The sample is an rectangular random matrix with real ind…
On basic graphs of symmetric graphs of valency five
Da-Wei Yang, Yan-Quan Feng, Jin Ho Kwak +1
A graph $\G$ is {\em symmetric} or {\em arc-transitive} if its automorphism group $\Aut(\G)$ is transitive on the arc set of the graph, and $\G$ is {\em basic} if $\Aut(\G)$ has no…
Lifting graph automorphisms along solvable regular covers
Haimiao Chen, Jin Ho Kwak
A {\em solvable} cover of a graph is a regular cover whose covering transformation group is solvable. In this paper, we show that a solvable cover of a graph can be decomposed into…
2-Groups that factorise as products of cyclic groups, and regular embeddings of complete bipartite graphs
Shaofei Du, Gareth Jones, Jin Ho Kwak +2
We classify those 2-groups G which factorise as a product of two disjoint cyclic subgroups A and B, transposed by an automorphism of order 2. The case where G is metacyclic having…
Classification of nonorientable regular embeddings of complete bipartite graphs
Jin Ho Kwak, Young Soo Kwon
A 2-cell embedding of a graph into a closed (orientable or nonorientable) surface is called regular if its automorphism group acts regularly on the flags - mutually incident ve…