Multiple contractions of permutation arrays

Carmen Amarra, Dom Vito A. Briones, Manuel Joseph C. Loquias

Given a permutation $\sigma$ on $n$ symbols $\{0,1,\dots ,n-1\}$ and an integer $1\le m\le n-1$, the $m$th contraction of $\sigma$ is the permutation ${\sigma }^{{\mathsf{CT}}^m}$ on $n-m$ symbols…