We give a novel upper bound on graph energy in terms of the vertex cover number, and present a complete characterization of the graphs whose energy equals twice their matching number.

中文翻译：

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关于图能量界的顶点覆盖数或匹配数的注记

我们根据顶点覆盖数给出了图能量的一个新的上限，并给出了其能量等于其匹配数两倍的图的完整表征。