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A graph $G$ is well-covered if all its maximal stable sets have the same size, denoted by alpha(G) (M. D. Plummer, 1970). If for any $k$ the $k$-th coefficient of a polynomial I(G;x) is equal to the number of stable sets of cardinality $k$…

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

If for any $k$ the $k$-th coefficient of a polynomial $I(G;x)$ is equal to the number of stable sets of cardinality $k$ in the graph $G$, then it is called the independence polynomial of $G$ (Gutman and Harary, 1983). Alavi, Malde, Schwenk…

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

If for any $k$ the $k$-th coefficient of a polynomial I(G;x) is equal to the number of stable sets of cardinality $k$ in the graph $G$, then it is called the independence polynomial of $G$ (Gutman and Harary, 1983). Let $a$ be the size of a…

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

If for any k the k-th coefficient of a polynomial I(G;x)is equal to the number of stable sets of cardinality k in graph G, then it is called the independence polynomial of G (Gutman and Harary, 1983). A graph G is very well-covered…

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

The number of stable sets of cardinality $k$ in graph $G$ is the $k$-th coefficient of the independence polynomial of $G$ (I. Gutman and F. Harary, 1983). In 1990, Y. O. Hamidoune proved that for any claw-free graph, its independence…

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

The independence polynomial $i(G,x)$ of a graph $G$ is the generating function of the numbers of independent sets of each size. A graph of order $n$ is very well-covered if every maximal independent set has size $n/2$. Levit and Mandrescu…

Combinatorics · Mathematics 2017-09-26 Jason I. Brown , Ben Cameron

An independent set in a graph is a set of pairwise non-adjacent vertices. The independence number $\alpha{(G)}$ is the size of a maximum independent set in the graph $G$. The independence polynomial of a graph is the generating function for…

Discrete Mathematics · Computer Science 2022-03-08 Ron Yosef , Matan Mizrachi , Ohr Kadrawi

The independence polynomial $I(G, x)$ of a graph $G$ is the polynomial in variable $x$ in which the coefficient $a_n$ on $x^n$ gives the number of independent subsets $S \subseteq V(G)$ of vertices of $G$ such that $|S| = n$. $I(G, x)$ is…

Combinatorics · Mathematics 2018-02-20 Patrick Bahls , Bailey Ethridge , Levente Szabo

A graph is well-covered if all its maximal independent sets are of the same cardinality (Plummer, 1970). If G is a well-covered graph, has at least two vertices, and G-v is well-covered for every vertex v, then G is a 1-well-covered graph…

Combinatorics · Mathematics 2016-12-13 Vadim E. Levit , Eugen Mandrescu

Let $I(G;x)$ denote the independence polynomial of a graph $G$. In this paper we study the unimodality properties of $I(G;x)$ for some composite graphs $G$. Given two graphs $G_1$ and $G_2$, let $G_1[G_2]$ denote the lexicographic product…

Combinatorics · Mathematics 2015-07-22 Bao-Xuan Zhu , Qinglin Lu

If alpha=alpha(G) is the maximum size of an independent set and s_{k} equals the number of stable sets of cardinality k in graph G, then I(G;x)=s_{0}+s_{1}x+...+s_{alpha}x^{alpha} is the independence polynomial of G. In this paper we prove…

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

An independent set in a graph is a collection of vertices that are not adjacent to each other. The cardinality of the largest independent set in $G$ is represented by $\alpha(G)$. The independence polynomial of a graph $G = (V, E)$ was…

Combinatorics · Mathematics 2023-08-21 Ohr Kadrawi , Vadim E. Levit

An independent set in a graph is a set of pairwise non-adjacent vertices, and a(G) is the size of a maximum independent set in the graph G. If s_{k} is the number of independent sets of cardinality k in G, then…

Discrete Mathematics · Computer Science 2013-03-12 Vadim E. Levit , Eugen Mandrescu

An independent set in a graph is a set of pairwise non-adjacent vertices, and alpha(G) is the size of a maximum independent set in the graph G. A matching is a set of non-incident edges, while mu(G) is the cardinality of a maximum matching.…

Discrete Mathematics · Computer Science 2011-05-12 Vadim E. Levit , Eugen Mandrescu

In this paper, we study the independence polynomial $P_G(x)$ of a finite simple graph $G$, with emphasis on the evaluation at $x=-1$, symmetry, and its connection with the $h$-polynomial of the edge ideal of $G$. For big star graphs, we…

Combinatorics · Mathematics 2026-03-18 Takayuki Hibi , Selvi Kara , Dalena Vien

The independence polynomial of a graph is termed {\it stable} if all its roots are located in the left half-plane $\{z \in \mathbb{C} : \mathrm{Re}(z) \leq 0\}$, and the graph itself is also referred to as stable. Brown and Cameron…

Combinatorics · Mathematics 2025-06-02 Guo Chen , Bo Ning , Jianhua Tu

A graph with at most two vertices of the same degree is called antiregular (Merris 2003), maximally nonregular (Zykov 1990) or quasiperfect (Behzad, Chartrand 1967). If s_{k} is the number of independent sets of cardinality k in a graph G,…

Discrete Mathematics · Computer Science 2010-07-07 Vadim E. Levit , Eugen Mandrescu

Let $G$ be a simple graph of order $n$. An independent set in a graph is a set of pairwise non-adjacent vertices. The independence polynomial of $G$ is the polynomial $I(G,x)=\sum_{k=0}^{n} s(G,k) x^{k}$, where $s(G,k)$ is the number of…

Combinatorics · Mathematics 2013-03-14 Mohammad Reza Oboudi

The independence polynomial of a graph is the generating polynomial for the number of independent sets of each size, and its roots are called {\em independence roots}. We investigate the stability of such polynomials, that is, conditions…

Combinatorics · Mathematics 2018-02-08 Jason Brown , Ben Cameron

A polynomial is said to be unimodal if its coefficients are non-decreasing and then non-increasing. The domination polynomial of a graph $G$ is the generating function of the number of dominating sets of each cardinality in $G$. In…

Combinatorics · Mathematics 2024-11-05 Iain Beaton , Sam Schoonhoven
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