Results 31 to 40 of about 1,270 (74)

On Independent Domination in Planar Cubic Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2019
A set S of vertices in a graph G is an independent dominating set of G if S is an independent set and every vertex not in S is adjacent to a vertex in S.
Abrishami Gholamreza   +2 more
doaj   +1 more source

Bounds on Watching and Watching Graph Products

open access: yesDiscussiones Mathematicae Graph Theory, 2022
A watchman’s walk for a graph G is a minimum-length closed dominating walk, and the length of such a walk is denoted (G). We introduce several lower bounds for such walks, and apply them to determine the length of watchman’s walks in several grids.
Dyer Danny, Howell Jared
doaj   +1 more source

Improving the Efficiency of Fuzzy Graphs and Their Complements Using Some Influencing Parameters

open access: yesJournal of Mathematics, Volume 2025, Issue 1, 2025.
This study focuses on constructing optimal network structures for fuzzy graph (FG) products. In graph theory, the complement of a FG product is essential since it analyses alternate interactions between the vertices. Such a complement is used to represent situations in which specific connections are deliberately excluded, which helps to understand ...
A. Meenakshi   +4 more
wiley   +1 more source

On The Total Roman Domination in Trees

open access: yesDiscussiones Mathematicae Graph Theory, 2019
A total Roman dominating function on a graph G is a function f : V (G) → {0, 1, 2} satisfying the following conditions: (i) every vertex u for which f(u) = 0 is adjacent to at least one vertex v for which f(v) = 2 and (ii) the subgraph of G induced by ...
Amjadi Jafar   +2 more
doaj   +1 more source

On Well-Covered Direct Products

open access: yesDiscussiones Mathematicae Graph Theory, 2022
A graph G is well-covered if all maximal independent sets of G have the same cardinality. In 1992 Topp and Volkmann investigated the structure of well-covered graphs that have nontrivial factorizations with respect to some of the standard graph products.
Kuenzel Kirsti, Rall Douglas F.
doaj   +1 more source

The number of independent sets in a graph with small maximum degree

open access: yes, 2010
Let ${\rm ind}(G)$ be the number of independent sets in a graph $G$. We show that if $G$ has maximum degree at most $5$ then $$ {\rm ind}(G) \leq 2^{{\rm iso}(G)} \prod_{uv \in E(G)} {\rm ind}(K_{d(u),d(v)})^{\frac{1}{d(u)d(v)}} $$ (where $d(\cdot)$ is ...
David Galvin   +4 more
core   +1 more source

A Study on Variants of Status Unequal Coloring in Graphs and Its Properties

open access: yesJournal of Mathematics, Volume 2024, Issue 1, 2024.
Let G∧ be a simple connected graph with vertex set ϑG∧ and edge set ξG∧. The status of a vertex p∈ϑG∧ is defined as ∑q≠pd(p, q). A subset P of ϑG∧ is called a status unequal dominating set (stu‐dominating set) of G∧; for every q∈ϑ−P, there exists p in P such that p and q are adjacent and st(p) ≠ st(q).
Parvathy Gnana Sambandam   +4 more
wiley   +1 more source

Bipartite graphs with close domination and k-domination numbers

open access: yesOpen Mathematics, 2020
Let kk be a positive integer and let GG be a graph with vertex set V(G)V(G). A subset D⊆V(G)D\subseteq V(G) is a kk-dominating set if every vertex outside DD is adjacent to at least kk vertices in DD. The kk-domination number γk(G){\gamma }_{k}(G) is the
Ekinci Gülnaz Boruzanlı   +1 more
doaj   +1 more source

Squares and difference sets in finite fields [PDF]

open access: yes, 2013
For infinitely many primes p = 4k+1 we give a slightly improved upper bound for the maximal cardinality of a set B ⊂ Z p such that the difference set B−B contains only quadratic residues. Namely, instead of the ”trivial” bound |B| ≤ √p we prove |B √p
Bachoc, C.   +2 more
core  

Alliance free and alliance cover sets

open access: yes, 2008
A \emph{defensive} (\emph{offensive}) $k$-\emph{alliance} in $\Gamma=(V,E)$ is a set $S\subseteq V$ such that every $v$ in $S$ (in the boundary of $S$) has at least $k$ more neighbors in $S$ than it has in $V\setminus S$.
H. Fernau   +13 more
core   +1 more source

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