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Weakly Protected Points in Ordered Trees

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Abstract

In this paper, we enumerate the set of ordered trees with n edges according to the number of weakly protected points. Explicit formulas as well as generating functions are obtained. We also find that, as n goes to infinity, the proportion of weakly protected points among all vertices of ordered trees with n edges approaches 1/3.

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Acknowledgements

The authors wish to thank the referees and editor for their valuable suggestions which improved the quality of this paper. This work is supported by the National Natural Science Foundation of China (Grant No. 11861045) and the Hongliu Foundation of First-class Disciplines of Lanzhou University of Technology, China.

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  1. Department of Applied Mathematics, Lanzhou University of Technology, Lanzhou, 730050, Gansu, People’s Republic of China

    Lin Yang & Sheng-Liang Yang

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  1. Lin Yang
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  2. Sheng-Liang Yang
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Correspondence to Sheng-Liang Yang.

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Yang, L., Yang, SL. Weakly Protected Points in Ordered Trees. Graphs and Combinatorics 37, 775–788 (2021). https://doi.org/10.1007/s00373-021-02278-w

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