4 papers
Non-general type surfaces in P4, an update
Hirotachi Abo, Kristian Ranestad, Frank-Olaf Schreyer
A general algebraic surface cannot be embedded in P4. Proving a conjecture by Hartshorne and Lichtenbaum, Ellingsrud and Peskine showed that there is a degree bound for smooth rati…
Minimal Non-Weierstrass Semigroups
David Eisenbud, Frank-Olaf Schreyer
Let p in X be a point on a compact Riemann surface. The Weierstrass semigroup of p is the semigroup of pole orders of meromorphic functions on X that are regular at all but p. Hurw…
Hyperelliptic curves and Ulrich sheaves on the complete intersection of two quadrics
David Eisenbud, Frank-Olaf Schreyer
Using the connection between hyperelliptic curves, Clifford algebras, and complete intersections of two quadrics, we describe Ulrich bundles on and construct some of minima…
Commutative Algebra and Algebraic Geometry using OSCAR
Janko Boehm, Wolfram Decker, Frank-Olaf Schreyer
We give illustrative examples of how the computer algebra system OSCAR can support research in commutative algebra and algebraic geometry. We start with a thorough introduction to…