Counting Permutations that Avoid Many Patterns


Yonah BIERS-ARIEL, Haripriya CHAKRABORTY, John CHIARELLI, Bryan EK, Andrew LOHR, Jinyoung PARK, Justin SEMONSEN, Richard VOEPEL, Mingjia YANG, Anthony ZALESKI, and Doron ZEILBERGER

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Written: Dec, 2016-Feb. 28; Posted March 7, 2017. This version: March 8, 2017.

Exclusively published in the Personal Journal of Shalosh B. Ekhad and Doron Zeilberger and .

This paper presents a collection of experimental results regarding permutation pattern avoidance, focusing on cases where there are many patterns to be avoided. The choices of projects contained herein were made collectively by Dr. Z.'s Fall 2016 Experimental Mathematics.

Added March 8, 2017: It turns out that Toufik Mansour (see also wikipedia page), that, among many other things, is one of the greatest experts in the world on permutation patterns, along with his collaborators, has already explored the many facets of avoiding many patterns, in a very systematic way. So many of the discoveries reported in the latter sections of the present article has been already published by them. See the many references in Toufik Mansour's Email message that he kindly allowed us to post here.

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