Sangwook Kim, Seunghyun Seo, Heesung Shin Chonnam National University; Kangwon National University; Inha University
Abstract : In this paper, we enumerate the cardinalities for the set of all vertices of outdegree $\ge k$ at level $\ge \ell$ among all rooted ordered $d$-trees with $n$ edges. Our results unite and generalize several previous works in the literature.
Supported by : For the second author, this research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(NRF-2017R1D1A1B03033276). For the third author, this work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIP)(NRF-2017R1C1B2008269)