Gallai asked in 1984 if any k-critical graph on n vertices contains at least n distinct (k - 1)-critical subgraphs. The answer is trivial for k <= ......
In this paper, we complete the classification of transitive ovoids of finite Hermitian polar spaces.
期刊： COMBINATORICA, 2020; 40 (6)
TheHall ratioof a graphGis the maximum of |V(H)|/alpha(H) over all subgraphsHofG.It is easy to see that the Hall ratio of a graph is a lower bound for......
期刊： COMBINATORICA, 2020; 40 (1)
In this paper, we extend and refine previous Turan-type results on graphs with a given circumference. Let W-n,W- k,W- c be the graph obtained from a c......
期刊： COMBINATORICA, 2019; 39 (2)
The bilinear forms graph denoted here by Bil(q)(dxe) is a graph defined on the set of (dxe)-matrices (ed) over Fq with two matrices being adjacent if ......
期刊： COMBINATORICA, 2019; 39 (4)
Two sequences A and B of non-negative integers are called additive complements, if their sum contains all suffciently large integers. Let A(x) and B(x......
期刊： COMBINATORICA, 2018; 38 (4)
This paper contributes to the classification of finite 2-arc-transitive graphs. In [12], all the regular covers of complete bipartite graphs K-n,K-n w......
期刊： COMBINATORICA, 2018; 38 (5)
Let G be a bipartite graph with adjacency matrix A. If G has a unique perfect matching, then A has an inverse A(1) which is a symmetric integral matri......
期刊： COMBINATORICA, 2017; 37 (6)
The fractional arboricity of a graph G, denoted by I"(f) (G), is defined as . The celebrated Nash-Williams' Theorem states that a graph G can be parti......
期刊： COMBINATORICA, 2017; 37 (6)
Let G be a bridgeless graph and denote by cc(G) the shortest length of a cycle cover of G. Let V (2)(G) be the set of vertices of degree 2 in G. It is......
