Results 11 to 20 of about 13,009 (241)

Maximum nullity and zero forcing number of graphs with rank at most 4

open access: hybridCogent Mathematics & Statistics, 2018
Let G be a simple graph with n vertices. The rank of G is the number of non-zero eigenvalues of its adjacency matrix and denoted by rank(G).
Ebrahim Vatandoost, Katayoun Nozari
exaly   +4 more sources

Maximum generic nullity of a graph

open access: greenLinear Algebra and its Applications, 2009
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Leslie Hogben, Bryan L. Shader
openalex   +4 more sources

Zero forcing and maximum nullity for hypergraphs [PDF]

open access: greenDiscrete Applied Mathematics, 2019
The concept of zero forcing is extended from graphs to uniform hypergraphs in analogy with the way zero forcing was defined as an upper bound for the maximum nullity of the family of symmetric matrices whose nonzero pattern of entries is described by a given graph: A family of symmetric hypermatrices is associated with a uniform hypergraph and zeros ...
Leslie Hogben
openalex   +5 more sources

Line graphs: Their maximum nullities and zero forcing numbers [PDF]

open access: greenCzechoslovak Mathematical Journal, 2016
The main aim of this paper is to analyze the maximum nullity and zero forcing number, and their positive counterparts, for general families of line graphs associated with graphs possessing some specific properties. In [\textit{F. Barioli} et al., Linear Algebra Appl. 428, No.
Shaun Fallat, Abolghasem Soltani
openalex   +3 more sources

Two-connected signed graphs with maximum nullity at most two [PDF]

open access: greenLinear Algebra and its Applications, 2020
A signed graph is a pair $(G, )$, where $G=(V,E)$ is a graph (in which parallel edges are permitted, but loops are not) with $V=\{1,\ldots,n\}$ and $ \subseteq E$. The edges in $ $ are called odd and the other edges of $E$ even. By $S(G, )$ we denote the set of all symmetric $n\times n$ matrices $A=[a_{i,j}]$ with $a_{i,j}<0$ if $i$ and $j$ are ...
Marina Arav   +3 more
openalex   +4 more sources

Techniques for determining equality of the maximum nullity and the zero forcing number of a graph

open access: diamondThe Electronic Journal of Linear Algebra, 2021
It is known that the zero forcing number of a graph is an upper bound for the maximum nullity of the graph (see [AIM Minimum Rank - Special Graphs Work Group (F. Barioli, W. Barrett, S. Butler, S. Cioab$\breve{\text{a}}$, D. Cvetkovi$\acute{\text{c}}$, S. Fallat, C. Godsil, W. Haemers, L. Hogben, R. Mikkelson, S. Narayan, O. Pryporova, I.
Derek Young
openalex   +6 more sources

Tree Cover Number and Maximum Semidefinite Nullity of Some Graph Classes

open access: diamondThe Electronic Journal of Linear Algebra, 2020
Let $G$ be a graph with a vertex set $V$ and an edge set $E$ consisting of unordered pairs of vertices. The tree cover number of $G$, denoted $\tau(G)$, is the minimum number of vertex disjoint simple trees occurring as induced subgraphs of $G$ that cover all the vertices of $G$.
Rachel Domagalski, Sivaram K. Narayan
openalex   +4 more sources

A Zero‐Rank, Maximum Nullity Perfect Electromagnetic Wave Absorber

open access: greenAdvanced Optical Materials, 2019
AbstractElectromagnetic wave absorbers formed from a metamaterial layer are demonstrated and near‐perfect absorption is realized across much of the spectrum. Alternatively, an unpatterned low‐loss dielectric layer forms an absorber of coherent light and shows near‐zero reflectance and high absorption.
Jonathan Y. Suen   +2 more
openalex   +4 more sources

On the tree cover number and the positive semidefinite maximum nullity of a graph [PDF]

open access: green, 2018
For a simple graph $G=(V,E),$ let $\mathcal{S}_+(G)$ denote the set of real positive semidefinite matrices $A=(a_{ij})$ such that $a_{ij}\neq 0$ if $\{i,j\}\in E$ and $a_{ij}=0$ if $\{i,j\}\notin E$. The maximum positive semidefinite nullity of $G$, denoted $\operatorname{M}_+(G),$ is $\max\{\operatorname{null}(A)|A\in \mathcal{S}_+(G)\}.$ A tree cover
Chassidy Bozeman
openalex   +3 more sources

On the maximum positive semi-definite nullity and the cycle matroid of graphs

open access: diamondThe Electronic Journal of Linear Algebra, 2009
Let G = (V,E) be a graph with V = {1, 2, ¿ ,n}, in which we allow parallel edges but no loops, and let S+(G) be the set of all positive semi-definite n × n matrices A = [ai,j] with ai,j = 0 if i ¿ j and i and j are non-adjacent, ai,j ¿ 0 if i ¿ j and i and j are connected by exactly one edge, and ai,j e if i = j or i and j are connected by parallel ...
Hein van der Holst
openalex   +3 more sources

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