3 papers
math.CO2024
A curious symmetric decomposition of the (des, exc)-Eulerian polynomials
Shi-Mei Ma, Toufik Mansour, Yeong-Nan Yeh
One of the most central result in combinatorics says that the descent statistic and the excedance statistic are equidistribued over the symmetric group. As a continuation of the wo…
math.CO2024
Normal ordered grammars
Shi-Mei Ma, Toufik Mansour, Jean Yeh +1
We introduce the theory of normal ordered grammars, which gives a natural generalization of the normal ordering problem. To illustrate the main idea, we explore normal ordered gram…
math.CO2024
Sorting inversion sequences
Toufik Mansour, Howard Skogman, Rebecca Smith
We consider the avoidance of patterns in inversion sequences that relate sorting via sorting machines including data structures such as pop stacks and stacks. Such machines have be…