Twisted component sums of vector-valued modular forms

Abstract

We construct isomorphisms between spaces of vector-valued modular forms for the dual Weil representation and certain spaces of scalar-valued modular forms in the case that the underlying finite quadratic module $A$ has order $p$ or $2p$, where $p$ is an odd prime. The isomorphisms are given by twisted sums of the components of vector-valued modular forms. Our results generalize work of Bruinier and Bundschuh to the case that the components $F_{\gamma }$ of the vector-valued modular form are antisymmetric in the sense that $F_{\gamma }=-F_{-\gamma }$ for all $\gamma \in A$. As an application, we compute restrictions of Doi-Naganuma lifts of odd weight to components of Hirzebruch-Zagier curves.

13 pages

References in corpus (3)

• Remarks on the theta decomposition of vector-valued Jacobi forms
• Quasi-pullback of Borcherds products
• Half-Integral Weight Modular Forms and Modular forms for Weil representations