A Survey of Alternating Permutations

Abstract

A permutation a1a2 · · · an of 1, 2, . . . , n is alternating if a1 > a2 < a3 > a4 < · · · . We survey some aspects of the theory of alternating permutations, beginning with the famous result of André that if En is the number of alternating permutations of 1, 2, . . . , n, then P n≥0 En x n n! = sec x + tan x. Topics include refinements and q-analogues of… (More)

7 Figures and Tables

Topics

  • Presentations referencing similar topics