This week's seminars
Arithmetic Study Group: Phantom holomorphic projection
13 November 2018 14:00 in CM301
Orthogonal holomorphic projection of non-holomorphic modular forms is an
important tool for arithmetic applications.
Sturm's convolution method describes the holomorphic projection
reliably for Siegel modular forms of large weights.
We discuss Sturm's operator for small weights, the critical weight being
one larger than the group rank.
In this case it does not only produce the terms of holomorphic
projection but also so-called phantom terms.
We give a spectral theoretic interpretation of these phantom terms.