8 papers
Pseudodifferential Jacobi forms and Geometric Rankin-Cohen Brackets
Martin Raum, Anne V. Shepler
Cohen, Manin, and Zagier recovered the Rankin-Cohen bracket for modular forms from an action of the modular group on pseudodifferential operators whose coefficients are holomorphic…
Recursions for Mock Theta Functions
Matthew Ortiz, Martin Raum, Olav K. Richter
We establish weighted recursions for the coefficients of Ramanujan's third order mock theta functions and . Specifically, we apply a holomorphic projection operator to vect…
Weighted Recursions for Hurwitz Class Numbers
Matthew Ortiz, Martin Raum, Olav K. Richter
We establish new recursions for Hurwitz class numbers with polynomial weights. In contrast to previous recursions, our results decouple class numbers of even and odd discriminants.…
The Geometric Unitary Kudla Conjecture
Martin Raum
We prove that, over an arbitrary CM field, every symmetric formal Fourier-Jacobi series converges and equals the Fourier-Jacobi expansion of a genuine Hermitian Hilbert modular for…
Theta Cycles of Modular Forms Modulo
Scott Ahlgren, Martin Raum, Olav K. Richter
The theta cycle of a modular form modulo a prime is well understood. By contrast, the theta cycle modulo a power of is still mysterious and experimentally erratic. He…
Jacobi Forms of Affine Weight in Higher Cogenus and Nearly Holomorphic Functions
Jan Feldmann, Martin Raum
We describe Jacobi forms of vector-valued weights in terms of classical ones, extending previous results by Ibukiyama and Kyomura to the case of arbitrary cogenus. As in their resu…