“…For π ∈ M(G) and a nilpotent orbit O ⊂ g denote The study of Whittaker and generalized Whittaker models for representations of reductive groups over local fields evolved in connection with the theory of automorphic forms (via their Fourier coefficients), and has found important applications in both areas. See for example [Sh74,NPS73,Kos78,Kaw85,Ya86,Wall88a,Gin06,Jia07,GRS11]. From the point of view of representation theory, the space of generalized Whittaker models may be viewed as one kind of nilpotent invariant associated to smooth representations.…”