共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
4.
Let χ be an order c multiplicative character of a finite field and a binomial with . We study the twisted classical and T-adic Newton polygons of f. When , we give a lower bound of Newton polygons and show that they coincide if p does not divide a certain integral constant depending on .We conjecture that this condition holds if p is large enough with respect to by combining all known results and the conjecture given by Zhang-Niu. As an example, we show that it holds for . 相似文献
5.
《Discrete Mathematics》2022,345(1):112669
In this paper, we consider two kinds of spectral extremal questions. The first asks which graph attains the maximum Q-index over all graphs of order n and size ? The second asks which graph attains the maximum Q-index over all -bipartite graphs with edges? We solve the first question for , and the second question for . The maximum Q-index on connected -bipartite graphs is also determined for . 相似文献
6.
7.
8.
9.
10.
《Discrete Mathematics》2022,345(5):112786
Let G be a connected graph with vertices and edges. The nullity of G, denoted by , is the multiplicity of eigenvalue zero of the adjacency matrix of G. Ma, Wong and Tian (2016) proved that unless G is a cycle of order a multiple of 4, where is the elementary cyclic number of G and is the number of leaves of G. Recently, Chang, Chang and Zheng (2020) characterized the leaf-free graphs with nullity , thus leaving the problem to characterize connected graphs G with nullity when . In this paper, we solve this problem completely. 相似文献
11.
12.
13.
《Discrete Mathematics》2022,345(4):112774
Chvátal and Erdös (1972) [5] proved that, for a k-connected graph G, if the stability number , then G is Hamilton-connected () or Hamiltonian () or traceable (). Motivated by the result, we focus on tight sufficient spectral conditions for k-connected graphs to possess Hamiltonian s-properties. We say that a graph possesses Hamiltonian s-properties, which means that the graph is Hamilton-connected if , Hamiltonian if , and traceable if .For a real number , and for a k-connected graph G with order n, degree diagonal matrix and adjacency matrix , we have identified best possible upper bounds for the spectral radius , where Γ is either G or the complement of G, to warrant that G possesses Hamiltonian s-properties. Sufficient conditions for a graph G to possess Hamiltonian s-properties in terms of upper bounds for the Laplacian spectral radius as well as lower bounds of the algebraic connectivity of G are also obtained. Other best possible spectral conditions for Hamiltonian s-properties are also discussed. 相似文献
14.
15.
《Discrete Mathematics》2022,345(8):112904
Let be the minimum integer such that every plane graph with girth g at least , minimum degree and no -paths consisting of vertices of degree 2, where , has a 3-vertex with at least t neighbors of degree 2, where .In 2015, Jendrol' and Maceková proved . Later on, Hudák et al. established , Jendrol', Maceková, Montassier, and Soták proved , and , and we recently proved that and .Thus is already known for and all t. In this paper, we prove that , , and whenever . 相似文献
16.
This paper deals with the chemotaxis-growth system: , , in a smooth bounded domain with zero-flux boundary conditions, where μ, δ, and τ are given positive parameters. It is shown that the solution exponentially stabilizes to the constant stationary solution in the norm of as provided that and any given nonnegative and suitably smooth initial data fulfills , which extends the condition in [8]. 相似文献
17.
18.
19.
20.
《Discrete Mathematics》2021,344(12):112589
Let be the set of positive integers. For a nonempty set A of integers and every integer u, denote by the number of with such that . For a sequence S of positive integers, let be the counting function of S. The set is called a perfect difference set if for every positive integer u. In 2008, Cilleruelo and Nathanson (2008) [4] constructed dense perfect difference sets from dense Sidon sets. In this paper, as a main result, we prove that: let be an increasing function satisfying for any positive integer n, then for every Sidon set B and every function , there exists a set such that for every positive integer u and for all . 相似文献