3 papers
math.CO2026
The Grammatical Calculus
William Y. C. Chen
We give an introduction to the grammatical calculus, which originated from the umbral calculus of Rota. Context-free grammars arise in computer science. Differential operators can…
math.CO2026
A Grammatical Calculus for the Ramanujan Polynomials
William Y. C. Chen, Amy M. Fu, Elena L. Wang
The Ramanujan polynomials arise in three intertwined contexts. As remarked by BerndtEvans-Wilson, no combinatorial perspective seems to be alluded to in the original definition of…
math.CO2025
Increasing Binary Trees and the -Eulerian Polynomials
William Y. C. Chen, Amy M. Fu
In light of the grammar given by Ji for the -Eulerian polynomials introduced by Carlitz and Scoville, we provide a labeling scheme for increasing binary trees. In this set…