S Ananya ; Channa Basavayya ; D Ranganatha ; R Veeresha - Vanishing Coefficient Results in Three Families of Infinite q-products

hrj:17900 - Hardy-Ramanujan Journal, April 27, 2026, Volume 48 - 2025 - https://doi.org/10.46298/hrj.2026.17900
Vanishing Coefficient Results in Three Families of Infinite q-productsArticle

Authors: S Ananya 1; Channa Basavayya ; D Ranganatha ; R Veeresha

  • 1 Central University of Karnataka, India.


In the recent past, the work in the area of vanishing coefficients of infinite $q$-products has been taken to the forefront. Weaving the same thread as Ramanujan, Richmond, Szekeres, Andrews, Alladi, Gordon, Mc Laughlin, Baruah, Kaur, Tang, we further prove vanishing coefficients in arithmetic progressions moduli 5, 7, 11, 13, 17, 19 and 29 of the following four families of infinite products, where $\{X_{a,b,sm,km,u,v}(n)\}_{n\geq n_0}$, $\{Y_{a,b,sm,km,u,v}(n)\}_{n\geq n_0}$ and $\{Z_{a,b,sm,km,u,v}(n)\}_{n\geq n_0}$ are defined by\begin{align*}\sum_{n\geq n_0}^{\infty}X_{a,b,sm,km,u,v}(n)q^n:=&\p(q^{a},q^{sm-a};q^{sm})^u\p(q^{b},q^{km-b};q^{km})^v, \\\sum_{n\geq n_0}^{\infty}Y_{a,b,sm,km,u,v}(n)q^n:=&\p(q^{a},q^{sm-a};q^{sm})^u\p(-q^{b},-q^{km-b};q^{km})^v, \\\sum_{n\geq n_0}^{\infty}Z_{a,b,sm,km,u,v}(n)q^n:=&\p(-q^{a},-q^{sm-a};q^{sm})^u\p(q^{b},q^{km-b};q^{km})^v,\end{align*}here $a, b, s, k, u$ and $v$ are chosen in such a way that the infinite products in the right-hand side of the above are convergent and $n_0$ is an integer (possibly negative or zero) depending on $a, b, s, k, u$ and $v$. The proof uses the Jacobi triple product identity and the properties of Ramanujan general theta function.


Volume: Volume 48 - 2025
Published on: April 27, 2026
Accepted on: April 27, 2026
Submitted on: April 2, 2026
Keywords: 11B65, 11F27, 30B10, [MATH]Mathematics [math], [en] odd moduli, arithmetic progressions, products of theta functions, Vanishing coefficients