The construction of $q$-analogues via $_3φ_2$-series and $q$-difference equations
John M. Campbell
TL;DR
The paper develops a multiparameter EKHAD-normalization framework built on the $q$-Zeilberger algorithm to construct $q$-WZ pairs for ${}_{3}\phi_{2}$-series, enabling telescoping to relate sums of the form $\sum_{k} F(0,k)$ and $\sum_{n} G(n,0)$. This approach generalizes EKHAD-normalization beyond fixed seeds, yielding broad families of $q$-analogues for accelerated hypergeometric series and Ramanujan-type evaluations of universal constants such as $\pi$ and $\Gamma$-values with rational arguments. By applying the method to Ramanujan-type, Fabry--Guillera, Apéry, Zeilberger, and BBP-type formulas, the work produces numerous new $q$-analogues and demonstrates a versatile route to generate further identities via parameter specialization. The results illuminate the unifying role of ${}_{3}\phi_{2}$-series in $q$-analogue accelerations and open pathways for combinatorial and number-theoretic applications of multiparameter $q$-WZ methods.
Abstract
We apply the EKHAD-normalization method given in our recent work to obtain, via the $q$-version of Zeilberger's algorithm, $q$-WZ pairs $(F, G)$ such that $\sum_{k = 0}^{\infty} F(0, k)$ may be expressed as a basic hypergeometric series of the form ${}_{3}φ_2$ with multiple free parameters, and in such a way so that $\sum_{k=0}^{\infty} F(0, k) = \sum_{n=0}^{\infty} G(n, 0)$. In contrast to how previous applications of EKHAD-normalization relied on $q$-analogues for specific WZ pairs introduced by Guillera, our multiparameter approach provides a broad framework in the construction of $q$-analogues for accelerated series for universal constants such as $π$. We apply this multiparameter version of EKHAD-normalization to obtain and prove new $q$-analogues for accelerated hypergeometric series attributed to many authors, including (alphabetically) Adamchik and Wagon, Apéry, Chu, Chu and Zhang, Fabry, Guillera, Ramanujan, and Zeilberger.
