Results 61 to 70 of about 1,105 (94)

Antipodal graphs and digraphs

, 1991
International Journal of Mathematics and Mathematical Sciences, Volume 16, Issue 3, Page 579-586, 1993.
Garry Johns, Karen Sleno
wiley   +1 more source

A Survey on Packing Colorings

Discussiones Mathematicae Graph Theory, 2020
If S = (a1, a2, . . .) is a non-decreasing sequence of positive integers, then an S-packing coloring of a graph G is a partition of V (G) into sets X1, X2, . . .
Brešar Boštjan, Ferme Jasmina, Klavžar Sandi, Rall Douglas F.   +3 more
doaj   +1 more source

Coloring the vertices of a graph with mutual-visibility property

Open Mathematics
Given a graph GG, a mutual-visibility coloring of GG is a coloring of the vertices of GG satisfying the following. Two vertices x,y∈V(G)x,y\in V\left(G) can be colored with the same color, if there is a shortest x,yx,y-path whose internal vertices have ...
Klavžar Sandi, Kuziak Dorota, Tripodoro Juan Carlos Valenzuela, Yero Ismael G.   +3 more
doaj   +1 more source

A cospectral construction for the generalized distance matrix

Special Matrices
The generalized distance matrix of a graph is a matrix in which the (i,j)\left(i,j)th entry is a function, ff, of the distance between vertex ii and vertex jj.
Friesen Ori, Kolko Cecily, Layman Nick, Lorenzen Kate, Zaske Sarah, Zeigler Amy   +5 more
doaj   +1 more source

A Characterization for 2-Self-Centered Graphs

Discussiones Mathematicae Graph Theory, 2018
A graph is called 2-self-centered if its diameter and radius both equal to 2. In this paper, we begin characterizing these graphs by characterizing edge-maximal 2-self-centered graphs via their complements.
Shekarriz Mohammad Hadi, Mirzavaziri Madjid, Mirzavaziri Kamyar   +2 more
doaj   +1 more source

Bounds on F-index of tricyclic graphs with fixed pendant vertices

Open Mathematics, 2020
The F-index F(G) of a graph G is obtained by the sum of cubes of the degrees of all the vertices in G. It is defined in the same paper of 1972 where the first and second Zagreb indices are introduced to study the structure-dependency of total π-electron ...
Akram Sana, Javaid Muhammad, Jamal Muhammad   +2 more
doaj   +1 more source

The Second Neighbourhood for Bipartite Tournaments

Discussiones Mathematicae Graph Theory, 2019
Let T (X ∪ Y, A) be a bipartite tournament with partite sets X, Y and arc set A. For any vertex x ∈ X ∪Y, the second out-neighbourhood N++(x) of x is the set of all vertices with distance 2 from x.
Li Ruijuan, Sheng Bin
doaj   +1 more source

On Topological Indices of mth Chain Hex-Derived Network of Third Type

Frontiers in Physics, 2020
In theoretical chemistry, the numerical parameters that are used to characterize the molecular topology of graphs are called topological indices. Several physical and chemical properties like boiling point, entropy, heat formation, and vaporization ...
Yuhong Huo, Haidar Ali, Muhammad Ahsan Binyamin, Syed Sheraz Asghar, Usman Babar, Jia-Bao Liu   +5 more
doaj   +1 more source

Diameters of commuting graphs of matrices over semirings

, 2010
We calculate the diameters of commuting graphs of matrices over the binary Boolean semiring, the tropical semiring and an arbitrary nonentire commutative semiring.
Bukovšek, Damjana Kokol, Dolžan, David, Oblak, Polona   +2 more
core  

The Smallest Harmonic Index of Trees with Given Maximum Degree

Discussiones Mathematicae Graph Theory, 2018
The harmonic index of a graph G, denoted by H(G), is defined as the sum of weights 2/[d(u) + d(v)] over all edges uv of G, where d(u) denotes the degree of a vertex u. In this paper we establish a lower bound on the harmonic index of a tree T.
Rasi Reza, Sheikholeslami Seyed Mahmoud
doaj   +1 more source