3 papers
math.CO2026
Bijections between pattern-avoiding derangements and desarrangements
Alyssa G. Henke, Derek H. Stephens, Yan Zhuang
Derangements are permutations without fixed points, and are in bijection with desarrangements: permutations whose first non-descent is even, or equivalently, permutations without `…
math.CO2025
Restricted Jacobi permutations
Alyssa G. Henke, Kyle R. Hoffman, Derek H. Stephens +2
Jacobi permutations, introduced by Viennot in the context of Jacobi elliptic functions, are counted by the Euler numbers appearing in the series expansion $\sec x+\tan x=\s…
math.CO2024
Counting pattern-avoiding permutations by big descents
Sergi Elizalde, Johnny Rivera, Yan Zhuang
A descent of a permutation is called a big descent if ; denote the number of big descents of by .…