3 papers
math.AG2025
Kummer surfaces and quadratic line complexes in characteristic two
Toshiyuki Katsura, Shigeyuki Kondo
In this paper, we study the classical theory of quadratic line complexes and Kummer surfaces. A quadratic line complex is the intersection of the Grassmannian and a quadri…
math.AG2024
The 2-divisibility of divisors on K3 surfaces in characteristic 2
Toshiyuki Katsura, Shigeyuki KondÅ, Matthias Schütt
We show that K3 surfaces in characteristic 2 can admit sets of disjoint smooth rational curves whose sum is divisible by 2 in the Picard group, for each . More pr…
math.AG2024
Normal forms for quasi-elliptic Enriques surfaces and applications
Toshiyuki Katsura, Matthias Schütt, Matthias Schütt
We work out normal forms for quasi-elliptic Enriques surfaces and give several applications. These include torsors and numerically trivial automorphisms, but our main application i…