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Related papers: On $\alpha ^{++}$-Stable Graphs

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The stability number of a graph G, is the cardinality of a stable set of maximum size in G. If the stability number of G remains the same upon the addition of any edge, then G is called $\alpha ^{+}$-stable. G is a K\"{o}nig-Egervary graph…

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 maximum stable set, and mu(G) is the cardinality of a maximum matching in G. If alpha(G) + mu(G) equals its order, then G is a Koenig-Egervary graph. We call G…

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 maximum stable set, and mu(G) is the cardinality of a maximum matching in G. If alpha(G)+mu(G) equals its order, then G is a Konig-Egervary graph. In this paper…

Combinatorics · Mathematics 2011-01-25 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. If alpha(G-e) > alpha(G), then e is an alpha-critical edge, and if mu(G-e) < mu(G), then e is a mu-critical edge, where mu(G)…

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

The stability number alpha(G) of a graph G is the cardinality of a maximum stable set in G, xi(G) denotes the size of core(G), where core(G) is the intersection of all maximum stable sets of G. In this paper we prove that for a graph G…

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

The square of a graph G is the graph G^2 with the same vertex set as in G, and an edge of G^2 is joining two distinct vertices, whenever the distance between them in G is at most 2. G is a square-stable graph if it enjoys the property…

Discrete Mathematics · Computer Science 2015-03-17 Vadim E. Levit , Eugen Mandrescu

The independence number of a graph G, denoted by alpha(G), is the cardinality of an independent set of maximum size in G, while mu(G) is the size of a maximum matching in G, i.e., its matching number. G is a Konig-Egervary graph if its…

Discrete Mathematics · Computer Science 2009-11-26 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

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

We prove that if $G=(V,E)$ is an $\omega$-stable (respectively, superstable) graph with $\chi(G)>\aleph_0$ (respectively, $2^{\aleph_0}$) then $G$ contains all the finite subgraphs of the shift graph $\text{Sh}_n(\omega)$ for some $n$. We…

Logic · Mathematics 2021-03-23 Yatir Halevi , Itay Kaplan , Saharon Shelah

We characterize stability of graph C*-algebras by giving five conditions equivalent to their stability. We also show that if G is a graph with no sources, then C*(G) is stable if and only if each vertex in G can be reached by an infinite…

Operator Algebras · Mathematics 2007-05-23 Mark Tomforde

A set $S\subseteq V$ is \textit{independent} in a graph $G=\left( V,E\right) $ if no two vertices from $S$ are adjacent. The \textit{independence number} $\alpha(G)$ is the cardinality of a maximum independent set, while $\mu(G)$ is the…

Discrete Mathematics · Computer Science 2019-05-24 Vadim E. Levit , Eugen Mandrescu

For integers $k>\ell\ge0$, a graph $G$ is $(k,\ell)$-stable if $\alpha(G-S)\geq \alpha(G)-\ell$ for every $S\subseteq V(G)$ with $|S|=k$. A recent result of Dong and Wu [SIAM J. Discrete Math., 36 (2022) 229--240] shows that every…

Combinatorics · Mathematics 2024-04-03 Xiaonan Liu , Zi-Xia Song , Zhiyu Wang

Let $G$ be a graph without isolated vertices and let $\alpha(G)$ be its stability number and $\tau(G)$ its covering number. The {\it $\alpha_{v}$-cover} number of a graph, denoted by $\alpha_{v}(G)$, is the maximum natural number $m$ such…

Combinatorics · Mathematics 2013-09-02 Isidoro Gitler , Carlos E. Valencia

We start up the study of the stability of general graph pairs. This notion is a generalization of the concept of the stability of graphs. We say that a pair of graphs $(\Gamma,\Sigma)$ is stable if $Aut(\Gamma\times\Sigma) \cong…

Combinatorics · Mathematics 2020-11-02 Yan-Li Qin , Binzhou Xia , Jin-Xin Zhou , Sanming Zhou

The independence number $\alpha(G)$ is the cardinality of a maximum independent set, while $\mu(G)$ is the size of a maximum matching in $G$. If $\alpha(G)+\mu(G)$ equals the order of $G$, then $G$ is called a Konig-Egervary graph. The…

Combinatorics · Mathematics 2022-09-02 Vadim E. Levit , Eugen Mandrescu

We say that a graph G is $(k,\ell)$-stable if removing $k$ vertices from it reduces its independence number by at most $\ell$. We say that G is tight $(k,\ell)$-stable if it is $(k,\ell)$-stable and its independence number equals…

Combinatorics · Mathematics 2024-02-08 Dingding Dong , Sammy Luo

Let G be a simple graph with vertex set V(G). A subset S of V(G) is independent if no two vertices from S are adjacent. The graph G is known to be a Konig-Egervary if alpha(G) + mu(G)= |V(G)|, where alpha(G) denotes the size of a maximum…

Discrete Mathematics · Computer Science 2015-06-02 Adi Jarden , Vadim E. Levit , Eugen Mandrescu

Let $\alpha(G)$ denote the cardinality of a maximum independent set, while $\mu(G)$ be the size of a maximum matching in $G=\left( V,E\right) $. Let $\xi(G)$ denote the size of the intersection of all maximum independent sets. It is known…

Combinatorics · Mathematics 2024-04-22 Vadim E. Levit , Eugen Mandrescu
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