23 citations · 65 across the 26 of their papers we have counts for
27 papers
Modular forms via invariant theory
Fabien Cléry, Gerard van der Geer
We discuss two simple but useful observations that allow the construction of modular forms from given ones using invariant theory. The first one deals with elliptic modular forms a…
Picard modular forms and the cohomology of local systems on a Picard modular surface
Jonas Bergström, Gerard van der Geer
We formulate a detailed conjectural Eichler-Shimura type formula for the cohomology of local systems on a Picard modular surface associated to the group of unitary similitudes $\ma…
Covariants of binary sextics and modular forms of degree 2 with character
Fabien Cléry, Carel Faber, Gerard van der Geer
We use covariants of binary sextics to describe the structure of modules of scalar-valued or vector-valued Siegel modular forms of degree 2 with character, over the ring of scalar-…
On vector-valued Siegel modular forms of degree 2 and weight (j,2)
Fabien Cléry, Gerard van der Geer
We formulate a conjecture that describes the vector-valued Siegel modular forms of degree 2 and level 2 of weight Sym^j det^2 and provide some evidence for it. We construct such mo…
Exploring modular forms and the cohomology of local systems on moduli spaces by counting points
Gerard van der Geer
This is a report on a joint project in experimental mathematics with Jonas Bergström and Carel Faber where we obtain information about modular forms by counting curves over finite…
Rational correspondences between moduli spaces of curves defined by Hurwitz spaces
Gerard van der Geer, Alexis Kouvidakis
By associating to a curve C of genus g=2k and a pencil of degree d=k+1 the so-called trace curve (resp. the reduced trace curve) we define a rational map from the Hurwitz space of…