Congruences of Eisenstein series of level $\hat{I}{“}_1(N)$ via Dieudonné theory of formal groups

Ningchuan Zhang

In this paper, we give a new explanation of congruences of Eisenstein series of level $\hat{I}{“}_1(N)$ and character $\ddot{I}‡$. Our approach is based on Katz's algebro-geometric explanation of…