Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5777522 | Journal of Combinatorial Theory, Series A | 2017 | 38 Pages |
Abstract
A graph Î is called G-symmetric if it admits G as a group of automorphisms acting transitively on the set of ordered pairs of adjacent vertices. We give a classification of G-symmetric graphs Î with V(Î) admitting a nontrivial G-invariant partition B such that there is exactly one edge of Î between any two distinct blocks of B. This is achieved by giving a classification of (G,2)-point-transitive and G-block-transitive designs D together with G-orbits Ω on the flag set of D such that GÏ,L is transitive on Lâ{Ï} and Lâ©N={Ï} for distinct (Ï,L),(Ï,N)âΩ, where GÏ,L is the setwise stabilizer of L in the stabilizer GÏ of Ï in G. Along the way we determine all imprimitive blocks of GÏ on Vâ{Ï} for every 2-transitive group G on a set V, where ÏâV.
Related Topics
Physical Sciences and Engineering
Mathematics
Discrete Mathematics and Combinatorics
Authors
Teng Fang, Xin Gui Fang, Binzhou Xia, Sanming Zhou,