COMPUTING ISOGENY COVARIANT DIFFERENTIAL MODULAR FORMS

Abstract. We present the computation modulo p 2 and explicit formulas for the unique isogeny covariant differential modular form of order one and weight χ−p−1,−p called fjet, an isogeny covariant differential modular form of order two and weight χ −p 2 −p,−1,−1 denoted by fjethjet, and an isogeny covariant differential modular form hjet of order two and weight χ 1−p 2,0,−1. 1