2 papers
math.AG2019
The ring of modular forms of degree two in characteristic three
Gerard van der Geer
We determine the structure of the ring of Siegel modular forms of degree 2 in characteristic 3.
math.AG2019
Concomitants of Ternary Quartics and Vector-valued Siegel and Teichmüller Modular Forms of Genus Three
Fabien Cléry, Carel Faber, Gerard van der Geer
We show how one can use the representation theory of ternary quartics to construct all vector-valued Siegel modular forms and Teichmüller modular forms of degree 3. The relation be…