On trees covering chains or stars
英文摘要：
In this paper, in the context of the ``Dessins d'enfants'' theory, we give a combinatorial criterion for a plane tree to cover a tree from the classes of "chains" or "stars''. Besides, we discuss some applications of this result which are related to the arithmetical theory of torsion on curves.
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。
