3 papers
math.AG2025
An arithmetic analog of Klein's classification of finite subgroups of
Christian Liedtke, Matthew Satriano
Let be a number field with ring of integers . We describe and classify finite, flat, and linearly reductive subgroup schemes of over $\mathrm{Spe…
math.AC2025
On Noether's Degree Bound for Finite Group Schemes
Gregor Kemper, Christian Liedtke, Christiane Ott
This paper establishes Noether's classical degree bound for finite and linearly reductive group schemes. On the other hand, we provide examples of infinitesimal gro…
math.AG2025
On rational double points over nonclosed fields
Christian Liedtke, Matthew Satriano
We compute the equations of all rational double point singularities and we determine their types over perfect ground fields that arise as quotient singularities by finite linea…