3 papers
math.CO2026
The inversion number statistic for inversion sequences
Lora R. Du, Guo-Niu Han
Inversion sequences, also known as subexcedant sequences, form a fundamental class of objects in enumerative combinatorics. In this paper, we study the joint distribution of five s…
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…
math.CO2024
A Refinement of a Theorem of Diaconis-Evans-Graham
Lora R. Du, Kathy Q. Ji
The note is dedicated to refining a theorem by Diaconis, Evans, and Graham concerning successions and fixed points of permutations. This refinement specifically addresses non-adjac…