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arXiv 2402.13403math.CO
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关于具有禁止子图或指定子图的若干基于度的拓扑指标的极值

On extremal values of some degree-based topological indices with a forbidden or a prescribed subgraph

Dániel Gerbner

AI总结:

本文将 Xu 关于第二 Zagreb 指标在给定团数下的极值结果推广到其他基于度的拓扑指标,并借助子图计数加权和的方法研究禁止或指定子图条件下的极值问题。

摘要:

Xu 在 2011 年确定了团数为 $k$ 的 $n$ 个顶点图 $G$ 中第二 Zagreb 指标的最大值,并在额外假设 $G$ 连通时确定了其最小值。我们将这些结果推广到其他基于度的拓扑指标。第一个结果中团数的关键性质是 $G$ 不含 $K_{k+1}$,而第二个结果中的关键性质是 $G$ 包含一个 $K_{k+1}$。我们还将研究扩展到其他禁止子图或指定子图。我们的主要工具是证明若干基于度的拓扑指标等于 $G$ 的某些子图数量的加权和。

英文摘要:

Xu in 2011 determined the largest value of the second Zagreb index in an $n$-vertex graph $G$ with clique number $k$, and also the smallest value with the additional assumption that $G$ is connected. We extend these results to other degree-based topological indices. The key property of the clique number in the first result is that $G$ is $K_{k+1}$-free, while the key property in the second result is that $G$ contains a $K_{k+1}$. We also extend our investigations to other forbidden/prescribed subgraphs. Our main tool is showing that several degree-based topological indices are equal to the weighted sum of the number of some subgraphs of $G$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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