| Title: | The relation between the number of leaves  of a tree and its diameter (English) | 
| Author: | Qiao, Pu | 
| Author: | Zhan, Xingzhi | 
| Language: | English | 
| Journal: | Czechoslovak Mathematical Journal | 
| ISSN: | 0011-4642 (print) | 
| ISSN: | 1572-9141 (online) | 
| Volume: | 72 | 
| Issue: | 2 | 
| Year: | 2022 | 
| Pages: | 365-369 | 
| Summary lang: | English | 
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| Category: | math | 
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| Summary: | Let $L(n,d)$ denote the minimum possible number of leaves in a tree of order $n$ and diameter $d.$ Lesniak (1975) gave the lower bound $B(n,d)=\lceil 2(n-1)/d\rceil $ for $L(n,d).$ When $d$ is even, $B(n,d)=L(n,d).$ But when $d$ is odd, $B(n,d)$ is smaller than $L(n,d)$ in general. For example, $B(21,3)=14$ while $L(21,3)=19.$ In this note, we determine $L(n,d)$ using new ideas. We also consider the converse problem and determine the minimum possible diameter of a tree with given order and number of leaves. (English) | 
| Keyword: | leaf | 
| Keyword: | diameter | 
| Keyword: | tree | 
| Keyword: | spider | 
| MSC: | 05C05 | 
| MSC: | 05C12 | 
| MSC: | 05C35 | 
| idZBL: | Zbl 07547209 | 
| idMR: | MR4412764 | 
| DOI: | 10.21136/CMJ.2021.0492-20 | 
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| Date available: | 2022-04-21T18:59:40Z | 
| Last updated: | 2024-07-01 | 
| Stable URL: | http://hdl.handle.net/10338.dmlcz/150406 | 
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| Reference: | [1] Lesniak, L.: On longest paths in connected graphs.Fundam. Math. 86 (1975), 283-286. Zbl 0293.05141, MR 0396330, 10.4064/fm-86-3-283-286 | 
| Reference: | [2] Ore, O.: Theory of Graphs.Colloquium Publications 38. American Mathematical Society, Providence (1962). Zbl 0105.35401, MR 0150753, 10.1090/coll/038 | 
| Reference: | [3] West, D. B.: Introduction to Graph Theory.Prentice Hall, Upper Saddle River (1996). Zbl 0845.05001, MR 1367739 | 
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