A $q$-Exponential Operator Based on the Derivative of Order 1 and Summation of Bilateral Basic Hypergeometric Series
Ronald Orozco López
TL;DR
The paper introduces a novel $q$-exponential operator built from the $q^{\pm1}$-derivative of order 1 to derive summation formulas for bilateral basic hypergeometric series. It develops a robust calculus of order 1 and a parameter-augmented operator $\mathrm{E}_{q}(y\mathbf{D}_{q^{\pm1}}|q^b)$, then applies this framework to obtain closed forms for ${}_{0}\psi_{1}$, ${}_{1}\psi_{1}$, ${}_{1}\psi_{2}$, and ${}_{2}\psi_{2}$, including bilateral series whose terms are basic hypergeometric functions. The results unify Jacobi theta function identities with Ramanujan’s and Bailey-Daum summations, delivering a versatile toolbox for evaluating bilateral $q$-series. This work advances the toolkit for $q$-series and has potential implications for modular forms, combinatorics, and related areas of mathematical analysis.
Abstract
We use a new $q$-exponential operator based on the $q^{\pm1}$-derivative $\D_{q^{\pm1}}$ of order 1 to derive summation formulas for bilateral basic hypergeometric series ${}_{0}ψ_{1}$, ${}_{1}ψ_{1}$, ${}_{1}ψ_{2}$, and ${}_{2}ψ_{2}$. In addition, we provide summation formulas for bilateral series whose terms are basic hypergeometric functions.
