Abstract
In this paper, we determine the unique maximum (or minimum) extremal graph for general spectral radius, zeroth-order general Randić index, general sum-connectivity index, general Platt index, second Zagreb index and multiplicative Zagreb indices in the class of cacti with \(n\ge 4\) vertices and \(k\ge 0\) cycles. By applying our new result, we demonstrate the unique maximum extremal graph for general spectral radius, zeroth-order general Randić index, general sum-connectivity index, general Platt index, second Zagreb index and second multiplicative Zagreb index in the class of cacti with \(n\ge 4\) vertices. Furthermore, we also determine the unified maximum extremal graphs for general spectral radius, zeroth-order general Randić index and the second multiplicative Zagreb index in the class of cacti with \(n\ge 4\) vertices and \(k\ge 1\) pendant vertices.
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Acknowledgements
The authors would like to thank the referees for their valuable comments which lead to an improvement in the original manuscript. The first author is partially supported by NNSF of China (No. 11571123), Guangdong Province Ordinary University Characteristic Innovation Project (No. 2017KTSCX020). The third author is supported by the National Research Foundation of the Korean government with Grant No. 2017R1D1A1B03028642.
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Communicated by Xueliang Li.
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Liu, M., Yao, Y. & Das, K.C. Extremal Results for Cacti. Bull. Malays. Math. Sci. Soc. 43, 2783–2798 (2020). https://doi.org/10.1007/s40840-019-00837-2
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DOI: https://doi.org/10.1007/s40840-019-00837-2
Keywords
- Extremal graph
- Zeroth-order general Randić index
- General sum-connectivity index
- General Platt index
- Cactus graph