L-Series for Vector-Valued Weakly Holomorphic Modular Forms and Converse Theorems
Subong Lim, Wissam Raji
TL;DR
This paper develops a unified Laplace-transform framework for L-series attached to vector-valued modular objects, defining $L_f(\varphi)$ and its Mellin-family $L(s,f,\varphi)$ to capture a broad class of $L$-series for vector-valued weakly holomorphic modular forms, harmonic weak Maass forms, Jacobi forms, and Kohnen plus space forms. It proves analytic continuation and functional equations for these $L$-series and establishes converse theorems that characterize the corresponding modular objects from the analytic properties of their $L$-series, using tools such as Mellin transforms, theta decompositions, and Weil/metaplectic representations. The results cover both holomorphic and non-holomorphic components, relate the $igl(\xi_{2-k} \bigr)$-maps to cusp forms, and extend to Jacobi and half-integral weight plus-space settings, providing a cohesive approach to functoriality-type conclusions via Laplace-constructed $L$-series.
Abstract
We introduce the $L$-series of weakly holomorphic modular forms using Laplace transforms and give their functional equations. We then determine converse theorems for vector-valued harmonic weak Maass forms, Jacobi forms, and elliptic modular forms of half-integer weight in Kohnen plus space.
