Results 11 to 20 of about 704 (29)

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

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

A tight lower bound for the hardness of clutters

open access: yes, 2017
A {\it clutter} (or {\it antichain} or {\it Sperner family}) $L$ is a pair $(V,E)$, where $V$ is a finite set and $E$ is a family of subsets of $V$ none of which is a subset of another.
Mkrtchyan, Vahan, Sargsyan, Hovhannes
core   +1 more source

A vizing-type theorem for matching forests [PDF]

open access: yes, 2000
A well known Theorem of Vizing states that one can colour the edges of a graph by $\Delta +\alpha$ colours, such that edges of the same colour form a matching.
Keijsper, J.C.M.
core   +2 more sources

Star-factors of tournaments

open access: yes, 1997
Let S_m denote the m-vertex simple digraph formed by m-1 edges with a common tail. Let f(m) denote the minimum n such that every n-vertex tournament has a spanning subgraph consisting of n/m disjoint copies of S_m. We prove that m lg m - m lg lg m
Chen, Guantao   +2 more
core   +2 more sources

The Cartesian product of graphs with loops [PDF]

open access: yes, 2014
We extend the definition of the Cartesian product to graphs with loops and show that the Sabidussi-Vizing unique factorization theorem for connected finite simple graphs still holds in this context for all connected finite graphs with at least one ...
Christiaan E. Van De Woestijne   +7 more
core  

Eigenvalues and Perfect Matchings [PDF]

open access: yes
AMS classification: 05C50, 05C70, 05E30.graph;perfect matching;Laplacian matrix;eigenvalues.
Brouwer, A.E., Haemers, W.H.
core   +1 more source

Factor-Critical Property in 3-Dominating-Critical Graphs

open access: yes, 2006
A vertex subset $S$ of a graph $G$ is a dominating set if every vertex of $G$ either belongs to $S$ or is adjacent to a vertex of $S$. The cardinality of a smallest dominating set is called the dominating number of $G$ and is denoted by $\gamma(G)$.
Wang, Tao, Yu, Qinglin
core  

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