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A maximum stable set in a graph G is a stable set of maximum cardinality. S is called a local maximum stable set of G if S is a maximum stable set of the subgraph induced by the closed neighborhood of S. A greedoid (V,F) is called a local…

Discrete Mathematics · Computer Science 2011-02-08 Vadim E. Levit , Eugen Mandrescu

A maximum stable set in a graph G is a stable set of maximum cardinality. S is a local maximum stable set of G, if S is a maximum stable set of the subgraph induced by its closed neighborhood. Nemhauser and Trotter Jr. proved in 1975 that…

Combinatorics · Mathematics 2011-01-25 Vadim E. Levit , Eugen Mandrescu

A maximum stable set in a graph G is a stable set of maximum size. S is a local maximum stable set if it is a maximum stable set of the subgraph of G spanned by the union of S and N(S), where N(S) is the neighborhood of S. A matching M is…

Combinatorics · Mathematics 2007-05-23 Vadim E. Levit , Eugen Mandrescu

S is a local maximum stable set of a graph G, if the set S is a maximum stable set of the subgraph induced by its closed neighborhood. In (Levit, Mandrescu, 2002) we have proved that the family of all local maximum stable sets is a greedoid…

Combinatorics · Mathematics 2011-01-25 Vadim E. Levit , Eugen Mandrescu

A \textit{maximum stable set} in a graph $G$ is a stable set of maximum cardinality. $S$ is a \textit{local maximum stable set} of $G$, and we write $S\in\Psi(G)$, if $S$ is a maximum stable set of the subgraph induced by $S\cup N(S)$,…

Discrete Mathematics · Computer Science 2010-08-18 Vadim E. Levit , Eugen Mandrescu

A maximum stable set in a graph G is a stable set of maximum cardinality. S is a local maximum stable set if it is a maximum stable set of the subgraph of G spanned by the union of S and N(S), where N(S) is the neighborhood of S. One…

Combinatorics · Mathematics 2007-05-23 Vadim E. Levit , Eugen Mandrescu

The stability number of a graph G is the cardinality of a stability system of G (that is of a stable set of maximum size of G). A graph is alpha-stable if its stability number remains the same upon both the deletion and the addition of any…

Combinatorics · Mathematics 2007-05-23 Vadim E. Levit , Eugen Mandrescu

We find the maximum number of maximal independent sets in two families of graphs: all graphs with $n$ vertices and at most $r$ cycles, and all such graphs that are also connected. In addition, we characterize the extremal graphs.

Combinatorics · Mathematics 2007-05-23 Chee Ying Goh , Khee Meng Koh , Bruce E. Sagan , V. Vatter

A potted graph is a unicyclic graph such that its cycle contains a unique vertex with degree larger than 2. Given a graph $G$, a subset of $V(G)$ is a dissociation set of $G$ if it induces a subgraph with maximum degree at most one. A…

Combinatorics · Mathematics 2024-02-06 Zejun Huang , Xinwei Zhang

A stable set in a graph G is a set of mutually non-adjacent vertices, alpha(G) is the size of a maximum stable set of G, and core(G) is the intersection of all its maximum stable sets. In this paper we demonstrate that in a tree T, of order…

Combinatorics · Mathematics 2007-05-23 Vadim E. Levit , Eugen Mandrescu

A set S is independent in a graph G if no two vertices from S are adjacent. By core(G) we mean the intersection of all maximum independent sets. The independence number alpha(G) is the cardinality of a maximum independent set, while mu(G)…

Discrete Mathematics · Computer Science 2011-02-24 Vadim E. Levit , Eugen Mandrescu

G is a Koenig-Egervary graph provided alpha(G)+ mu(G)=|V(G)|, where mu(G) is the size of a maximum matching and alpha(G) is the cardinality of a maximum stable set. S is a local maximum stable set of G if S is a maximum stable set of the…

Combinatorics · Mathematics 2011-01-25 Vadim E. Levit , Eugen Mandrescu

The greedy algorithm A iterates over a set of uniformly sized independent sets of a given graph G and checks for each set S which non-neighbor of S, if any, is best suited to be added to S, until no more suitable non-neighbors are found for…

Data Structures and Algorithms · Computer Science 2015-05-05 Asbjørn Brændeland

Let $G$ be a graph with vertex set $V(G)$ and edge set $E(G)$. A set $I_0(G) \subseteq V(G)$ is a vertex independent set if no two vertices in $I_0(G)$ are adjacent in $G$. We study $\alpha_1(G)$, which is the maximum cardinality of a set…

Combinatorics · Mathematics 2024-06-25 Zekhaya B. Shozi

A coalition in a graph $G$ with vertex set $V$ consists of two disjoint sets $V_1, V_2\subset V$ such that neither $V_1$ nor $V_2$ is a dominating set, but the union $V_1\cup V_2$ is a dominating set in $G$. A partition of graph vertices is…

Combinatorics · Mathematics 2024-04-29 Andrey A. Dobrynin , Hamidreza Golmohammadi

A set $S\subseteq V(G)$ is independent (or stable) if no two vertices from $S$ are adjacent, and by $\mathrm{Ind}(G)$ we mean the set of all independent sets of $G$. A set $A\in\mathrm{Ind}(G)$ is critical (and we write $A\in CritIndep(G)$)…

Discrete Mathematics · Computer Science 2020-08-12 Vadim E. Levit , Eugen Mandrescu

A CIS graph is a graph in which every maximal stable set and every maximal clique intersect. A graph is well-covered if all its maximal stable sets are of the same size, co-well-covered if its complement is well-covered, and…

Combinatorics · Mathematics 2016-08-08 Edward Dobson , Ademir Hujdurović , Martin Milanič , Gabriel Verret

A square (0,1)-matrix X of order n > 0 is called fully indecomposable if there exists no integer k with 0 < k < n, such that X has a k by n-k zero submatrix. A stable set of a graph G is a subset of pairwise nonadjacent vertices. The…

Combinatorics · Mathematics 2007-05-23 Vadim E. Levit , Eugen Mandrescu

The stability number of a graph G, denoted by alpha(G), is the cardinality of a stable set of maximum size in G. A graph is well-covered if every maximal stable set has the same size. G is a Koenig-Egervary graph if its order equals…

Combinatorics · Mathematics 2007-05-23 Vadim E. Levit , Eugen Mandrescu

For a graph $G$ with vertex set $V$, let N($G$) denote the number of nonempty subsets of $V$ that induce a connected graph in $G$. In this paper, we focus on determining N($G$) for $G$ in the family $\mathbb{B}_n$ of $n$-vertex bicyclic…

Combinatorics · Mathematics 2026-03-31 Audace A. V. Dossou-Olory
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