Eisenstein series
In mathematics, a Klingen Eisenstein series is a Siegel modular form of weight "k" and degree "g" depending on another Siegel cusp form "f" of weight "k" and degree "r"&lt;"g", given by a series similar to an Eisenstein series. It is a generalization of the Siegel Eisenstein series, which is the special case when the Siegel cusp form is 1. Klingen Eisenstein series is introduced by .