4 papers
The distinguishing number of complete bipartite and crown graphs
Lei Chen, Alice Devillers, Luke Morgan +1
The distinguishing number of a permutation group $G\leqslant\Sym(Ω)$ is the minimum number of colours needed to colour in such a way that the only colour preserving element of…
Quasiprimitive and bi-quasiprimitive highly-arc-transitive digraphs and finite simple groups
Lei Chen, Cheryl Praeger
We extend the notion of an -normal quotient digraph of an -vertex-transitive digraph to that of an -subnormal quotient digraph. Using these concepts, together with biparti…
The normal closure of a homological genus 0 bounding pair map
Lei Chen, Weiyan Chen
Justin Lanier and the authors recently determined the group normally generated by a single bounding pair map of genus . We related this subgroup with the Chillingworth subgroup…
Exceptional groups and the -arc-transitivity of vertex-primitive digraphs, I
Fu-Gang Yin, Lei Chen
In this paper, we study the primitive actions of almost simple exceptional groups of Lie type on \(s\)-arc-transitive digraphs. Our motivation is the following question posed by Gi…