Philip B. Zhang

collaborators

3 papers

math.CO2026

Catalan structures arising from pattern-avoiding Stoimenow matchings and other Fishburn objects

Shuzhen Lv, Sergey Kitaev, Philip B. Zhang

In connection with Vassiliev's knot invariants, Stoimenow introduced in 1998 a class of matchings, also known as regular linearized chord diagrams. These matchings are linked to va…

math.CO2026

Simultaneous avoidance of length-4 patterns in ascent sequences

Qi Liu, Sergey Kitaev, Philip B. Zhang

Ascent sequences form a central class of combinatorial objects, as they are in bijection with several important families such as (2+2)-free posets, Stoimenow matchings, and other F…

math.CO2025

Descent generating polynomials for ( $n - 3$ )- and ( $n - 4$ )-stack-sortable (pattern-avoiding) permutations

Sergey Kitaev, Philip B. Zhang

In this paper, we find distribution of descents over $(n - 3)$ - and $(n - 4)$ -stack-sortable permutations in terms of Eulerian polynomials. Our results generalize the enumeration resul…

Catalan structures arising from pattern-avoiding Stoimenow matchings and other Fishburn objects

Simultaneous avoidance of length-4 patterns in ascent sequences

Descent generating polynomials for (n−3)- and (n−4)-stack-sortable (pattern-avoiding) permutations

Descent generating polynomials for ( $n - 3$ )- and ( $n - 4$ )-stack-sortable (pattern-avoiding) permutations