A graph Γ is said to be G-semisymmetric if it is regular and there exists a subgroup G of A := Aut(Γ) acting transitively on its edge set but not on its vertex set. In the case of G = A, we call Γ a semisymmetric g...A graph Γ is said to be G-semisymmetric if it is regular and there exists a subgroup G of A := Aut(Γ) acting transitively on its edge set but not on its vertex set. In the case of G = A, we call Γ a semisymmetric graph. The aim of this paper is to investigate (G-)semisymmetric graphs of prime degree. We give a group-theoretical construction of such graphs, and give a classification of semisymmetric cubic graphs of order 6p2 for an odd prime p.展开更多
A regular edge-transitive graph is said to be semisymmetric if it is not vertex-transitive.Let p be a prime.By Folkman[J.Combin.Theory 3(1967),215–232],there is no cubic semisymmetric graph of order 2p or 2p^2,and by...A regular edge-transitive graph is said to be semisymmetric if it is not vertex-transitive.Let p be a prime.By Folkman[J.Combin.Theory 3(1967),215–232],there is no cubic semisymmetric graph of order 2p or 2p^2,and by Hua et al.[Science in China A 54(2011),1937–1949],there is no cubic semisymmetric graph of order 4p^2.Lu et al.[Science in China A 47(2004),11–17]classified connected cubic semisymmetric graphs of order 6p^2.In this paper,for p>q≥5 two distinct odd primes,it is shown that the sufficient and necessary conditions which a connected cubic edge transitive bipartite graph of order 2qp^2 is semisymmetric.展开更多
A regular graph X is called semisymmetric if it is edge-transitive but not vertex-transitive. For G ≤ AutX, we call a G-cover X semisymmetric if X is semisymmetric, and call a G-cover X one-regular if Aut X acts regu...A regular graph X is called semisymmetric if it is edge-transitive but not vertex-transitive. For G ≤ AutX, we call a G-cover X semisymmetric if X is semisymmetric, and call a G-cover X one-regular if Aut X acts regularly on its arc-set. In this paper, we give the sufficient and necessary conditions for the existence of one-regular or semisymmetric Zn-Covers of K3,3. Also, an infinite family of semisymmetric Zn×Zn-covers of K3,3 are constructed.展开更多
The authors consider a quarter-symmetric metric connection in a P-Sasakian manifold and study the second order parallel tensor in a P-Sasakian manifold with respect to the quarter-symmetric metric connection. Then Ric...The authors consider a quarter-symmetric metric connection in a P-Sasakian manifold and study the second order parallel tensor in a P-Sasakian manifold with respect to the quarter-symmetric metric connection. Then Ricci semisymmetric P-Sasakian manifold with respect to the quarter-symmetric metric connection is considered. Next the authors study ξ-concircularly flat P-Sasakian manifolds and concircularly semisymmetric P-Sasakian manifolds with respect to the quarter-symmetric metric connection. Furthermore, the authors study P-Sasakian manifolds satisfying the condition Z(ξ,Y)·S=0,where Z,S are the concircular curvature tensor and Ricci tensor respectively with respect to the quarter-symmetric metric connection. Finally, an example of a 5-dimensional P-Sasakian manifold admitting quarter-symmetric metric connection is constructed.展开更多
基金This work was supported partly by the National Natural Science Foundation of China(Grant Nos.19831050,10171006)the Doctoral Program Foundation of Institutions of Higher Education of China(Grant No.2000000102).
文摘A graph Γ is said to be G-semisymmetric if it is regular and there exists a subgroup G of A := Aut(Γ) acting transitively on its edge set but not on its vertex set. In the case of G = A, we call Γ a semisymmetric graph. The aim of this paper is to investigate (G-)semisymmetric graphs of prime degree. We give a group-theoretical construction of such graphs, and give a classification of semisymmetric cubic graphs of order 6p2 for an odd prime p.
基金Supported by the National Natural Science Foundation of China(Nos.11301159,11671030,11601132,11501176)the Education Department of Henan Science and Technology Research Key Project(No.13A110543)
文摘A regular edge-transitive graph is said to be semisymmetric if it is not vertex-transitive.Let p be a prime.By Folkman[J.Combin.Theory 3(1967),215–232],there is no cubic semisymmetric graph of order 2p or 2p^2,and by Hua et al.[Science in China A 54(2011),1937–1949],there is no cubic semisymmetric graph of order 4p^2.Lu et al.[Science in China A 47(2004),11–17]classified connected cubic semisymmetric graphs of order 6p^2.In this paper,for p>q≥5 two distinct odd primes,it is shown that the sufficient and necessary conditions which a connected cubic edge transitive bipartite graph of order 2qp^2 is semisymmetric.
基金NSF of China (Project No.10571013)NSF of He'nan Province of China
文摘A regular graph X is called semisymmetric if it is edge-transitive but not vertex-transitive. For G ≤ AutX, we call a G-cover X semisymmetric if X is semisymmetric, and call a G-cover X one-regular if Aut X acts regularly on its arc-set. In this paper, we give the sufficient and necessary conditions for the existence of one-regular or semisymmetric Zn-Covers of K3,3. Also, an infinite family of semisymmetric Zn×Zn-covers of K3,3 are constructed.
基金supported by the National Natural Science Foundation of China(Nos.11871275,11371194).
文摘The authors consider a quarter-symmetric metric connection in a P-Sasakian manifold and study the second order parallel tensor in a P-Sasakian manifold with respect to the quarter-symmetric metric connection. Then Ricci semisymmetric P-Sasakian manifold with respect to the quarter-symmetric metric connection is considered. Next the authors study ξ-concircularly flat P-Sasakian manifolds and concircularly semisymmetric P-Sasakian manifolds with respect to the quarter-symmetric metric connection. Furthermore, the authors study P-Sasakian manifolds satisfying the condition Z(ξ,Y)·S=0,where Z,S are the concircular curvature tensor and Ricci tensor respectively with respect to the quarter-symmetric metric connection. Finally, an example of a 5-dimensional P-Sasakian manifold admitting quarter-symmetric metric connection is constructed.
