Let $K$ be a quadratic imaginary number field of discriminant $d$. For $t\in \mathbb{N}$ let ${𝔒}_t$ denote the order of conductor $t$ in $K$ and $j\left({𝔒}_t\right)$ its modular invariant which is known to generate the ring class field modulo $t$ over $K$. The coefficients of the minimal equation of $j\left({𝔒}_t\right)$ being quite large Weber considered in [We] the functions $f,f_1,f_2,{\gamma }_2,{\gamma }_3$ defined below and thereby obtained simpler generators of the ring class fields. Later on the singular values of these functions played a crucial role in Heegner’s solution [He] of the class...

Let $F$ be an imaginary quadratic field and $𝒪$ its ring of integers. Let $𝔫\subset 𝒪$ be a non-zero ideal and let $p\>5$ be a rational inert prime in $F$ and coprime with $𝔫$. Let $V$ be an irreducible finite dimensional representation of ${\overline{𝔽}}_p\left[{\mathrm{GL}}_2\left({𝔽}_{p^2}\right)\right]$. We establish that a system of Hecke eigenvalues appearing in the cohomology with coefficients in $V$ already lives in the cohomology with coefficients in ${\overline{𝔽}}_p\otimes de{t}^e$ for some $e\ge 0$; except possibly in some few cases.

The theory of Whittaker functors for $G{L}_n$ is an essential technical tools in Gaitsgory’s proof of the Vanishing Conjecture appearing in the geometric Langlands correspondence. We define Whittaker functors for $G𝕊p_4$ and study their properties. These functors correspond to the maximal parabolic subgroup of $G𝕊p_4$, whose unipotent radical is not commutative.We also study similar functors corresponding to the Siegel parabolic subgroup of $G𝕊p_4$, they are related with Bessel models for $G𝕊p_4$ and Waldspurger models for $G{L}_2$.We...