Project IV (MATH4072) 2015-16


Topics in Modular Forms

Jens Funke

Description

In this project, I offer, based on the second term of the Elliptic Functions Course last year, several topics in the theory of modular forms. Among these are
  • Rankin-Selberg Method. This method was originally developed by Rankin and Selberg to improve Hecke's bound on the growth of the Ramanujan tau-function, the Fourier coefficients of the discriminant function. It is a beautiful fusion of ideas and techniques from theory of modular forms and analytic number theory.
  • Theta Series and Eisenstein Series: the Siegel-Weil Formula. We have seen that a theta series is typically not an Eisenstein series (essentially, only when it was forced to be one since the underlying space was one-dimensional). However, a certain linear combination of theta series is an Eisenstein series. This is the theme of the celebrated Siegel Maass formula. It yields beautiful arithmetic formulas such as a formula for the sum of 3 squares.
  • Modular Forms and the Partition Function: The partition function is one of the most classical objects in combinatorial number theory. It has been studied extensively, in particular by Ramanujan. Recently, the theory of modular forms has yielded spectacular progress.
  • Modular Forms, Theta Series and Algebraic Number Theory: Let K be an imaginary quadratric field. Then every ideal class of K gives rises to a positive definite quadratic form which gives rise to a theta series. In this way we can study the arithmetic of K using modular forms. The connection goes actually much deeper and is very conceptual. It is an instant of the celebrated Langlands Programme; one of the most fundamental theme in mathematics of our time.

Depending on interest we can also look at other topics in the theory of modular forms, such as its connections to elliptic curves.

Resources

Depend on the chosen topic. For further questions feel free to see me.

Prerequisites

  • Elliptic functions III.
  • For some of the topics Number Theory III and/or Representation Theory IV will be helpful.

email: J Funke