In this paper, we consider the unimodality of the principal eigenvector of graphs. A unimodal lemma of the principal eigenvector on internal paths is obtained. This unimodal lemma is used to establish a cycle version of Li–Feng transformation with respect to the spectral radius. Another application of unimodal lemma is to determine the unicyclic graph with minimal spectral radius.

中文翻译：

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主特征向量的单峰性及其应用

在本文中，我们考虑图的主要特征向量的单峰性。获得内部路径上本征向量的单峰引理。该单峰引理用于建立相对于光谱半径的李峰变换的循环形式。单峰引理的另一个应用是确定具有最小光谱半径的单环图。