Bounds on the Spectral Radius of Graphs with e Edges
نویسندگان
چکیده
We give upper bounds for the spectral radius of a graph with e edges provided that there is no complete graph with e edges. Our bounds are sharp for (i) the complete graphs with one, two, or three edges removed; (ii) the complete graph with one added vertex and edge. Let G be a undirected graph with e edges and without loops. Then G is represented by its adjacency O-l symmetric matrix A with zero trace. Denote by p(G) = p(A) the spectral radius of G. It is of interest to find p(e), the maximum spectral radius of all G having e edges. Clearly, p(e) is achieved for a connected graph. Moreover p(e) is an increasing function of e. For
منابع مشابه
Sharp Bounds on the PI Spectral Radius
In this paper some upper and lower bounds for the greatest eigenvalues of the PI and vertex PI matrices of a graph G are obtained. Those graphs for which these bounds are best possible are characterized.
متن کاملOn Complementary Distance Signless Laplacian Spectral Radius and Energy of Graphs
Let $D$ be a diameter and $d_G(v_i, v_j)$ be the distance between the vertices $v_i$ and $v_j$ of a connected graph $G$. The complementary distance signless Laplacian matrix of a graph $G$ is $CDL^+(G)=[c_{ij}]$ in which $c_{ij}=1+D-d_G(v_i, v_j)$ if $ineq j$ and $c_{ii}=sum_{j=1}^{n}(1+D-d_G(v_i, v_j))$. The complementary transmission $CT_G(v)$ of a vertex $v$ is defined as $CT_G(v)=sum_{u in ...
متن کاملBounds for the Co-PI index of a graph
In this paper, we present some inequalities for the Co-PI index involving the some topological indices, the number of vertices and edges, and the maximum degree. After that, we give a result for trees. In addition, we give some inequalities for the largest eigenvalue of the Co-PI matrix of G.
متن کاملOn Zagreb Energy and edge-Zagreb energy
In this paper, we obtain some upper and lower bounds for the general extended energy of a graph. As an application, we obtain few bounds for the (edge) Zagreb energy of a graph. Also, we deduce a relation between Zagreb energy and edge-Zagreb energy of a graph $G$ with minimum degree $delta ge2$. A lower and upper bound for the spectral radius of the edge-Zagreb matrix is obtained. Finally, we ...
متن کاملA note on the bounds of Laplacian-energy-like-invariant
The Laplacian-energy-like of a simple connected graph G is defined as LEL:=LEL(G)=∑_(i=1)^n√(μ_i ), Where μ_1 (G)≥μ_2 (G)≥⋯≥μ_n (G)=0 are the Laplacian eigenvalues of the graph G. Some upper and lower bounds for LEL are presented in this note. Moreover, throughout this work, some results related to lower bound of spectral radius of graph are obtained using the term of ΔG as the num...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2001