English

Parity of coefficients of mock theta functions

Number Theory 2021-06-07 v2 Combinatorics

Abstract

We study the parity of coefficients of classical mock theta functions. Suppose gg is a formal power series with integer coefficients, and let c(g;n)c(g;n) be the coefficient of qnq^n in its series expansion. We say that gg is of parity type (a,1a)(a,1-a) if c(g;n)c(g;n) takes even values with probability aa for n0n\geq 0. We show that among the 44 classical mock theta functions, 21 of them are of parity type (1,0)(1,0). We further conjecture that 19 mock theta functions are of parity type (12,12)(\frac{1}{2},\frac{1}{2}) and 4 functions are of parity type (34,14)(\frac{3}{4},\frac{1}{4}). We also give characterizations of nn such that c(g;n)c(g;n) is odd for the mock theta functions of parity type (1,0)(1,0).

Keywords

Cite

@article{arxiv.2007.03664,
  title  = {Parity of coefficients of mock theta functions},
  author = {Liuquan Wang},
  journal= {arXiv preprint arXiv:2007.03664},
  year   = {2021}
}

Comments

41 pages, accepted by the Journal of Number Theory in 2021