English

Some $q$-congruences arising from certain identities

Number Theory 2020-03-25 v1 Combinatorics

Abstract

In this paper, by constructing some identities, we prove some qq-analogues of some congruences. For example, for any odd integer n>1n>1, we show that \begin{gather*} \sum_{k=0}^{n-1} \frac{(q^{-1};q^2)_k}{(q;q)_k} q^k \equiv (-1)^{(n+1)/2} q^{(n^2-1)/4} - (1+q)[n] \pmod{\Phi_n(q)^2},\\ \sum_{k=0}^{n-1}\frac{(q^3;q^2)_k}{(q;q)_k} q^k \equiv (-1)^{(n+1)/2} q^{(n^2-9)/4} + \frac{1+q}{q^2}[n]\pmod{\Phi_n(q)^2}, \end{gather*} where the qq-Pochhanmmer symbol is defined by (x;q)0=1(x;q)_0=1 and (x;q)k=(1x)(1xq)(1xqk1)(x;q)_k = (1-x)(1-xq)\cdots(1-xq^{k-1}) for k1k\geq1, the qq-integer is defined by [n]=1+q++qn1[n]=1+q+\cdots+q^{n-1} and Φn(q)\Phi_n(q) is the nn-th cyclotomic polynomial. The qq-congruences above confirm some recent conjectures of Gu and Guo.

Keywords

Cite

@article{arxiv.2003.10883,
  title  = {Some $q$-congruences arising from certain identities},
  author = {Chen Wang and He-Xia Ni},
  journal= {arXiv preprint arXiv:2003.10883},
  year   = {2020}
}

Comments

7 pages

R2 v1 2026-06-23T14:25:31.193Z