Results 21 to 30 of about 157 (120)
Special Matrices, 2019 Given a combinatorially symmetric matrix A whose graph is a tree T and its eigenvalues, edges in T can be classified in four categories, based upon the change in geometric multiplicity of a particular eigenvalue, when the edge is removed.
Toyonaga Kenji
doaj +1 more source
Discussiones Mathematicae Graph Theory, 2022 A branch at a vertex x in a tree is a maximal subtree containing x as an endvertex. The branch-weight of x is the maximum number of edges in any branch at x.
Shang Jen-Ling
doaj +1 more source
Special Matrices, 2017 We take as given a real symmetric matrix A, whose graph is a tree T, and the eigenvalues of A, with their multiplicities. Each edge of T may then be classified in one of four categories, based upon the change in multiplicity of a particular eigenvalue ...
Toyonaga Kenji, Johnson Charles R.
doaj +1 more source
Total Roman {2}-Dominating Functions in Graphs
Discussiones Mathematicae Graph Theory, 2022 A Roman {2}-dominating function (R2F) is a function f : V → {0, 1, 2} with the property that for every vertex v ∈ V with f(v) = 0 there is a neighbor u of v with f(u) = 2, or there are two neighbors x, y of v with f(x) = f(y) = 1.
Ahangar H. Abdollahzadeh +3 more
doaj +1 more source
Some improved bounds on two energy-like invariants of some derived graphs
Open Mathematics, 2019 Given a simple graph G, its Laplacian-energy-like invariant LEL(G) and incidence energy IE(G) are the sum of square root of its all Laplacian eigenvalues and signless Laplacian eigenvalues, respectively. This paper obtains some improved bounds on LEL and
Cui Shu-Yu, Tian Gui-Xian
doaj +1 more source
The bipartite Laplacian matrix of a nonsingular tree
Special Matrices, 2023 For a bipartite graph, the complete adjacency matrix is not necessary to display its adjacency information. In 1985, Godsil used a smaller size matrix to represent this, known as the bipartite adjacency matrix.
Bapat Ravindra B. +2 more
doaj +1 more source
Use of a Cytobrush for Sampling the Ear Canal of Dogs With Otitis Externa
Veterinary Dermatology, Volume 37, Issue 2, Page 227-235, April 2026.Cytological examination of the ear canal is essential for evaluating dogs with otitis externa (OE). The conventional sampling method uses a swab. However, the cytobrush (gynaecological cervical brush), already used for cytological collection from other anatomical sites, has not been adequately investigated for this purpose in dogs with OE.
Nicoly Radaeli Atanasio +3 more
wiley +1 more source
The Product Connectivity Banhatti Index of A Graph
Discussiones Mathematicae Graph Theory, 2019 Let G = (V, E) be a connected graph with vertex set V (G) and edge set E(G). The product connectivity Banhatti index of a graph G is defined as, PB(G)=∑ue1dG(u)dG(e)$PB(G) = \sum\nolimits_{ue} {{1 \over {\sqrt {{d_G}(u){d_G}(e)} }}}$ where ue means that ...
Kulli V.R. +2 more
doaj +1 more source
New Sharp Extremal Bounds for the Randić Index of Trees With Prescribed Roman Domination Number
Discrete Dynamics in Nature and Society, Volume 2026, Issue 1, 2026.The Randić index is a classical degree‐based topological index that captures branching features of a graph and has broad applications in chemical graph theory and related network models. Roman domination is a defense‐inspired covering concept in which vertices are assigned protective labels so that every unprotected vertex is adjacent to a strongly ...
Waqar Ali +4 more
wiley +1 more source
Trees with Unique Least Central Subtrees
Discussiones Mathematicae Graph Theory, 2018 A subtree S of a tree T is a central subtree of T if S has the minimum eccentricity in the join-semilattice of all subtrees of T. Among all subtrees lying in the join-semilattice center, the subtree with minimal size is called the least central subtree ...
Kang Liying, Shan Erfang
doaj +1 more source