Winnie Li – Pennsylvania State University

Modular forms for noncongruence subgroups: an introduction

Modular forms for congruence subgroups have been studied for over one century.
There are fabulous results and remarkable applications. On the other hand, the
arithmetic of modular forms for noncongruence subgroups is much less understood.
Nonetheless there are very interesting questions in this area waiting to be explored.
In this two-part talk we shall compare the developments in both areas, and discuss
important open problems and review recent progress on noncongruence forms.