English

Generalized Ismail's argument and $(f,g)$-expansion formula

Combinatorics 2007-05-23 v2

Abstract

As further development of earlier works on the (f,g)(f,g)-inversion, the present paper is devoted to the (f,g)(f,g)-difference operator and the representation problem or an expansion formula of analytic functions. A recursive formula and the Leibniz formula for the (f,g)(f,g)-difference operator of the product of two functions are established. The resulting expansion formula not only unifies the qq-analogue of the Lagrange inversion formula of Gessel and Stanton (thus, a qq-expansion formula of Liu) for qq-series but also systematizes the "Ismail's argument". In the meantime, a rigorous analytic proof of the (1xy,xy)(1-xy,x-y)-expansion formula with respect to geometric series, along with a proof of the previously unknown fact that it is equivalent to a qq-analogue of the Lagrange inversion formula due to Gessel and Stanton, is presented. As applications, new proofs of several well-known summation and transformation formulas are investigated.

Keywords

Cite

@article{arxiv.math/0608674,
  title  = {Generalized Ismail's argument and $(f,g)$-expansion formula},
  author = {Xinrong Ma},
  journal= {arXiv preprint arXiv:math/0608674},
  year   = {2007}
}

Comments

31 pages

R2 v1 2026-07-22T17:41:30.948Z