 Before the work of Zwegers led to a general method for constructing them, most examples were given as basic hypergeometric functions, but this is largely a historical accident, and most mock theta functions have no known simple expression in terms of such functions.The "trivial" mock theta functions are the (holomorphic) modular forms of weight 1/2, which were classified by , who showed that they could all be written in terms of theta functions of 1-dimensional lattices.The following examples use the q-Pochhammer symbols formula_18 which are defined as