Some remarks on very-well-poised 8φ7 series

Abstract. Nonpolynomial basic hypergeometric eigenfunctions of the Askey–Wilson second order difference operator are known to be expressible as very-well-poised 8φ7 series. In this paper we use this fact to derive various basic hypergeometric and theta function identities. We relate most of them to identities from the existing literature on basic hypergeometric series. This leads for example to a new derivation of a known quadratic transformation formula for very-well-poised 8φ7 series. We also provide a link to Chalykh’s theory on (rank one, BC type) Baker–Akhiezer functions. Key words: very-well-poised basic hypergeometric series; Askey–Wilson functions; quadratic transformation formulas; theta functions 2010 Mathematics Subject Classification: 33D15; 33D45