Ramanujan theta function

English

Etymology

Named after mathematician Template:W.

Proper noun

1. Template:Lb A theta function that generalizes the form of the Jacobi theta functions while capturing their general properties. It is defined as: $f(a,b)=\sum _{n=-\mathrm{\infty }}^{\mathrm{\infty }}{a}^{\frac{n(n+1)}{2}}{b}^{\frac{n(n-1)}{2}}$ for |ab| < 1.