2 papers
math.CO2026
Revisiting -Derangement Numbers via Decorated Permutations
Kathy Q. Ji
This paper aims to provide a direct combinatorial proof of the Gessel-Wachs formula for -derangement numbers in the setting of decorated permutations, without using the -bino…
math.CO2024
New refinements of Narayana polynomials and Motzkin polynomials
Janet J. W. Dong, Lora R. Du, Kathy Q. Ji +1
Chen, Deutsch and Elizalde introduced a refinement of the Narayana polynomials by distinguishing between old (leftmost child) and young leaves of plane trees. They also provided a…