Counting pattern-avoiding permutations by big descents

Sergi Elizalde, Johnny Rivera, Yan Zhuang

A descent $k$ of a permutation $\pi ={\pi }_1{\pi }_2\dots {\pi }_n$ is called a big descent if ${\pi }_k>{\pi }_{k+1}+1$; denote the number of big descents of $\pi$ by $\mathrm{bdes}(\pi )$. We study…