A function is said to be modular (or "elliptic modular") if it satisfies: 1.f is meromorphic in the upper half-plane H, 2.f(A τ) = f(τ) for every matrix A in the modular group Γ, 3. The Laurent series of f has the form f(τ) = sum_(n = - m)^∞ a(n) e^(2π i n τ) (Apostol 1997, p. 34). Every rational function of Klein's absolute invariant J is a modular function, and every modular function can be expressed as a rational function of J. Modular functions are special cases of modular forms, but not vice versa.
We guarantee you’ll find the right tutor, or we’ll cover the first hour of your lesson.