Ascent-Descent Young Diagrams and Pattern Avoidance in Alternating Permutations

Ravi Jagadeesan

Abstract


We investigate pattern avoidance in alternating permutations and an alternating analogue of Young diagrams. In particular, using an extension of Babson and West's notion of shape-Wilf equivalence described in our recent paper (with N. Gowravaram), we generalize results of Backelin, West, and Xin and Ouchterlony to alternating permutations. Unlike Ouchterlony and Bóna's bijections, our bijections are not the restrictions of Backelin, West, and Xin's bijections to alternating permutations. This paper is the second of a two-paper series presenting the work of Beyond alternating permutations: Pattern avoidance in Young diagrams and tableaux (with N. Gowravaram, arXiv:1301.6796v1). The first paper in the series is Beyond alternating permutations: Pattern avoidance in Young diagrams and tableaux (with N. Gowravaram, Electronic Journal of Combinatorics 20(4):#P17, 2013).


Keywords


pattern avoidance; alternating permutation; shape-Wilf equivalence

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