



























An independent set in a graph is a set of pairwise non-adjacent vertices. The independence number $α{(G)}$ is the size of a maximum independent set in the graph $G$. The independence polynomial of a graph is the generating function for the sequence of numbers of independent sets of each size. In other words, the $k$-th coefficient of the independence polynomial equals the number of independent sets comprised of $k$ vertices. For instance, the degree of the independence polynomial of the graph $G$ is equal to $α{(G)}$. In 1987, Alavi, Malde, Schwenk, and Erd{ö}s conjectured that the independence polynomial of a tree is unimodal. In what follows, we provide support to this assertion considering trees with up to $20$ vertices. Moreover, we show that the corresponding independence polynomials are log-concave and, consequently, unimodal. The algorithm computing the independence polynomial of a given tree makes use of a database of non-isomorphic unlabeled trees to prevent repeated computations.
此内容由惯性聚合(RSS阅读器)自动聚合整理,仅供阅读参考。 原文来自 — 版权归原作者所有。