Recently, Gu et al. [N.S.S. Gu, N.Y. Li, T. Mansour, 2-Binary trees: Bijections and related issues, Discrete Math. 308 (2008) 1209-1221] introduced 2-binary trees and 2-plane trees which are closely related to ternary trees. In this note, we study the 2-noncrossing tree, a noncrossing tree in which each vertex is colored black or white and there is no ascent (u. v) such that both the vertices Li and v are colored black. By using the representation of Panholzer and Prodinger for noncrossing trees, we find a correspondence between the set of 2-noncrossing trees of it edges with a black root and the set of 5-ary trees with n internal vertices (C) 2009 Elsevier B V. All rights reserved.
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机译：最近，Gu等人。 [N.S.S. Gu N.Y. Li，T.Mansour，2-二叉树：双射和相关问题，离散数学。 308（2008）1209-1221]介绍了与三叉树密切相关的2-二叉树和2-平面树。在本注释中，我们研究了2个非交叉树，这是一个非交叉树，其中每个顶点都被着色为黑色或白色，并且没有上升（u。v）使得顶点Li和v都被着色为黑色。通过使用Panholzer和Prodinger的非交越树的表示，我们找到了边缘为黑根的2个非交会树的集合与具有n个内部顶点的5元树的集合之间的对应关系（C）2009 Elsevier B V 。 版权所有。
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