6 papers
Deligne-Lusztig varieties whose canonical divisors have negativity
Ulrich Görtz, Stefan Schröer
We investigate compactified Deligne-Lusztig varieties whose canonical divisor, when expressed as a linear combination of boundary divisors, has all coefficients strictly negative o…
Surfaces of general type and sl_2-triples
Stefan Schröer, Nikolaos Tziolas
The sl_2-triples play a fundamental role for the structure theory of Lie algebras, and representation theory in general. Here we investigate sl_2-triples of global vector fields on…
K3 surfaces over small number fields and Kummer constructions in families
Stefan Schröer
We construct K3 surfaces over number fields that have good reduction everywhere. These do not exists over the rational numbers, by results of Abrashkin and Fontaine. Our surfaces e…
Varieties with free tangent sheaves
Damian Rössler, Stefan Schröer
We coin the term \emph{-trivial varieties} to denote smooth proper schemes over ground fields whose tangent sheaf is free. Over the complex numbers, this are precisely the a…
The Iskovskih Theorem for regular surfaces over imperfect fields
Andrea Fanelli, Stefan Schröer
We generalize Iskovskih's theorem about surfaces without irregularity and bigenus from the smooth case to regular surfaces over arbitrary fields, with special focus on the case of…
Rational points in coarse moduli spaces and twisted representations
Fabian Korthauer, Stefan Schröer
We study moduli spaces and moduli stacks for representations of associative algebras in Azumaya algebras, in rather general settings. We do not impose any stability condition and w…