In the classical setting, the derivative of a holomorphic modular form of integral weight on the complex upper half-plane is not in general a modular form since the derivative fails to satisfy the correct transformation properties. However, R. A. Rankin and H. Cohen were able to construct particular bilinear differential operators sending modular forms to modular forms. These Rankin—Cohen operators have several interesting properties and have been studied by D. Zagier, Y. Choie, T. Ibukiyama, and others.

In this talk I will discuss the classical Rankin—Cohen operators, and some of their generalizations to automorphic forms in higher dimension, including ​​constructing Rankin—Cohen​ type differential operators on Hermitian modular forms of signature (n,n).