Construction and non-vanishing of a family of vector-valued Siegel Poincaré series

Abstract: Using Poincar\'e series of $ K $-finite matrix coefficients of integrable antiholomorphic discrete series representations of $ \mathrm{Sp}{2n}(\mathbb R) $, we construct a spanning set for the space $ S\rho(\Gamma) $ of Siegel cusp forms of weight $ \rho $ for $ \Gamma $, where $ \rho $ is an irreducible polynomial representation of $ \mathrm{GL}n(\mathbb C) $ of highest weight $ \omega\in\mathbb Z^n $ with $ \omega_1\geq\ldots\geq\omega_n>2n $, and $ \Gamma $ is a discrete subgroup of $ \mathrm{Sp}{2n}(\mathbb R) $ commensurable with $ \mathrm{Sp}_{2n}(\mathbb Z) $. Moreover, using a variant of Mui\'c's integral non-vanishing criterion for Poincar\'e series on unimodular locally compact Hausdorff groups, we prove a result on the non-vanishing of constructed Siegel Poincar\'e series.