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arXiv · 1203.0795

Non-Contiguous Pattern Avoidance in Binary Trees

Michael Dairyko·Lara Pudwell·Samantha Tyner·Casey Wynn
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Abstract

In this paper we consider the enumeration of binary trees avoiding non-contiguous binary tree patterns. We begin by computing closed formulas for the number of trees avoiding a single binary tree pattern with 4 or fewer leaves and compare these results to analogous work for contiguous tree patterns. Next, we give an explicit generating function that counts binary trees avoiding a single non-contiguous tree pattern according to number of leaves. In addition, we enumerate binary trees that simultaneously avoid more than one tree pattern. Finally, we explore connections between pattern-avoiding trees and pattern-avoiding permutations.

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Michael Dairyko, Lara Pudwell, Samantha Tyner, Casey Wynn. 2012-03-05. Non-Contiguous Pattern Avoidance in Binary Trees. https://arxiv.org/abs/1203.0795

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