3 papers
math.CO2026
A combinatorial proof for the positivity of the normalized Jacobi triple product tails
Xiangyu Ding, Lisa Hui Sun
For , we prove that \[ [q^n z^s]J_k(z,q)\geq 0, \qquad (n\geq 0,\ s\in\mathbb Z) \] for the normalized Jacobi triple product tails \[ J_k(z,q) = \frac{ \sum_{j=k}^{\infty}…
math.NT2025
Proof of Merca's stronger conjecture on truncated Jacobi triple product series
Xiangyu Ding, Lisa Hui Sun
In the study of theta series and partition functions, Andrews and Merca, Guo and Zeng independently conjectured that a truncated Jacobi triple product series has nonnegative coeffi…
math.CO2025
Truncated theta series from the Bailey lattice
Xiangyu Ding, Lisa Hui Sun
In 2012, Andrews and Merca obtained a truncated version of Euler's pentagonal number theorem and showed the nonnegativity related to partition functions. Meanwhile, Andrews-Merca a…