Extended Weil representations: the finite field cases
摘要
It is well-known (cf. Weil, Gérardin’s works) that there are two different Weil representations of a symplectic group over an odd finite field. By a twisted action, we show that they can be reorganized into a representation of a projective symplectic similitude group. We also discuss the even field case by following Genestier–Lysenko and Gurevich–Hadani’s works on geometric Weil representations in characteristic two. As a result, we approach some of their results from the lattice model, which is inspired by Mœglin–Vignéras–Waldspurger, Prasad and Takeda’s works.