Let ${\mathbb{G}}_n^2$ be the set of 2-domination critical connected graphs on $n$ vertices. This paper identifies the graphs with the maximal ($Q$-) index in ${\mathbb{G}}_n^2$.

中文翻译：

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关于2-支配临界图的(Q-)指数

让${\mathbb{G}}_n^2$是 2 支配临界连通图的集合$n$顶点。本文用最大 ($问$-) 索引${\mathbb{G}}_n^2$.