2 papers
math.CO2025
Difference ascent sequences and related combinatorial structures
Yongchun Zang, Robin D. P. Zhou
Ascent sequences were introduced by Bousquet-Mélou, Claesson, Dukes and Kitaev, and are in bijection with unlabeled -free posets, Fishburn matrices, permutations avoiding a…
math.CO2024
On the enumeration of permutations avoiding chains of patterns
Robin D. P. Zhou, Yongchun Zang
In 2019, Bóna and Smith introduced the notion of strong pattern avoidance, saying that a permutation strongly avoids a pattern if and both avoid . Recent…