Recursions for Mock Theta Functions

Abstract

We establish weighted recursions for the coefficients of Ramanujan's third order mock theta functions $f$ and $\ddot{I}‰$. Specifically, we apply a holomorphic projection operator to vector-valued Rankin-Cohen brackets of completed mock theta series and their shadows. By employing a vector-valued framework, we exploit the vanishing of certain spaces of vector-valued cusp forms. Our proof is AI-assisted and prioritizes accessibility, allowing for straightforward customization and replication within the broader research community.