Rankin-Cohen type differential operators on Hermitian modular forms

We construct Rankin-Cohen type differential operators on Hermitian modular forms of signature (n, n). The bilinear differential operators given here specialize to the original Rankin-Cohen operators in the case n=1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$n=1$$\end{document}, and more generally satisfy some analogous properties, including uniqueness. Our approach builds on previous work by Eholzer-Ibukiyama in the case of Siegel modular forms, together with results of Kashiwara-Vergne on the representation theory of unitary groups.