12 papers
Inseparable Kummer surfaces
Yuya Matsumoto
We introduce an inseparable version of Kummer surfaces. It is defined as a supersingular K3 surface in characteristic 2 with 16 smooth rational curves forming a certain configurati…
Supersingular reduction of Kummer surfaces in residue characteristic
Yuya Matsumoto
Given an abelian surface , defined over a discrete valuation field and having good reduction, does the attached Kummer surface also have good reduction? In this…
Torsors over the Rational Double Points in Characteristic
Christian Liedtke, Gebhard Martin, Yuya Matsumoto
We study torsors under finite group schemes over the punctured spectrum of a singularity in positive characteristic. We show that the Dieudonné module of the (loc,loc)-par…
Linearly Reductive Quotient Singularities
Christian Liedtke, Gebhard Martin, Yuya Matsumoto
We study isolated quotient singularities by finite and linearly reductive group schemes (lrq singularities for short) and show that they satisfy many, but not all, of the known pro…
Purely inseparable coverings of rational double points in positive characteristic
Yuya Matsumoto
We classify purely inseparable morphisms of degree between rational double points (RDPs) in characteristic . Using such morphisms, we refine a result of Artin that any R…
Inseparable maps on -valued local cohomology groups of non-taut rational double point singularities and the height of K3 surfaces
Yuya Matsumoto
We consider rational double point singularities (RDPs) that are non-taut, which means that the isomorphism class is not uniquely determined from the dual graph of the minimal resol…