Seymour's Second‐Neighborhood Conjecture states that every directed graph whose underlying graph is simple has at least one vertex $v$ such that the number of vertices of out‐distance two from $v$ is at least as large as the number of vertices of out‐distance one from it. We present alternative statements of the conjecture in the language of linear algebra.

中文翻译：

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从另一个角度看西摩的第二邻里猜想

Seymour的第二邻域猜想指出，其底层图很简单的每个有向图都有至少一个顶点 $v$ 这样，距离为2的顶点的数目 $v$至少与一个顶点之间的距离相等。我们用线性代数的语言提出猜想的替代陈述。