【摘 要】
：
For any graph G, G together with sufficiently many isolated vertices is the competition graph of some acyclic digraph.The competition number k(G) of a graph G i
【机 构】
：
SchoolofMathematicsandInformationScience,ShijiazhuangUniversity,Shijiazhuang050035,P.R.China
论文部分内容阅读
For any graph G, G together with sufficiently many isolated vertices is the competition graph of some acyclic digraph.The competition number k(G) of a graph G is defined to be the smallest number of such isolated vertices.In general, it is hard to compute the competition number k(G) for a graph G and characterizing a graph by its competition number has been one of important research problems in the study of competition graphs.A Halin graph is a planar graph consisting of a tree with no vertex of degree two and a cycle connecting the leaves of the tree.
其他文献
颈动脉严重狭窄是缺血性卒中的重要原因之一，颈动脉支架成形术前后，脑血流动力学变化研究甚少，本研究用磁共振灌注方法观察了症状性颈动脉狭窄在支架植入前后颅内血流动力学
Unimodality problems often arise in combinatorics, analysis, algebra, geometry, probability and statistics.In this topic, we will report some recent advance in
Epidemiology of Multiple SclerosisPrevalence gradients in Northern Hemisphere-North of 37th parallet(125 cases/100,000population)-South of 37th parallet(70 case
Alzheimer disease is characterized Pathologically by· Senile plaque (SP)------Aβ peptide· Neurofibrillary tangles (NFTs)------hyperphosphorylated tau· Neuro
In a recent systematic study, C.Sandon and F.Zanello offered 30 conjectured identities for partitions.In this lecture, we provide proofs for all 30 conjectures
Bizley studied a generalization of Dyck paths from (0, 0) to (pd, qd) (gcd(p, q) =1), which never go below the line py =qx with step set {(0, 1), (1, 0)}, and e
Let G be a graph with a nonzero Laplacian eigenvalue μ of multiplicity k.A line star set for μ in G is a set Y of k edges of G such that μ is not a Laplacian
Let A be a magic square of even order n.A is a Yang Hui type magic square with t-powered sum if for each e =2, 3, … , t, the sum of the elements of the first n
For a given sequence {zn}n≥0 of positive real numbers, {zn}n≥0 is said to be log-concave (or log-convex) if z2n ≥ zn-1zn+1 (or zn2 ≤ zn-1zn+1) for all n ≥