THE NUMBER OF PLANAR TREES

Abstract

By a planar tree is meant a realization of a tree in the plane, and by an isomorphism between two planar trees is meant a mapping which is not only an isomorphism in the usual sense of trees but which also preserves the clockwise cyclic order of edges about each node. Explicit formulae are given for each of the following: (1) the number of nonisomorphic unrooted planar trees with n edges, (2) the number of nonisomorphic rooted planar trees with n edges, and (3) the number of nonisomorphic rooted planar trees with n edges such that the root is incident on exactly k edges, of which one is distinguished.

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Document Details

Document Type
Technical Report
Publication Date
Sep 01, 1969
Accession Number
AD0696413

Entities

People

  • David W. Walkup

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  • Boeing

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  • Mathematics

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  • Graph Algorithms and Convex Optimization.