A combinatorial interpretation for Schreyer's tetragonal invariants
Journal Article
2015
Permanent link to this Item
Authors
Journal Title
Documenta Mathematica
Link to Journal
Journal ISSN
Volume Title
Publisher
Publisher
Faculty
License
Series
Abstract
Schreyer has proved that the graded Betti numbers of a canonical tetragonal curve are determined by two integers b(1) and b(2), associated to the curve through a certain geometric construction. In this article we prove that in the case of a smooth projective tetragonal curve on a toric surface, these integers have easy interpretations in terms of the Newton polygon of its defining Laurent polynomial. We can use this to prove an intrinsicness result on Newton polygons of small lattice width.
Description
Reference:
Castryck, W. & Cools, F. 2015. A combinatorial interpretation for Schreyer's tetragonal invariants. Documenta Mathematica. 20(4):903 - 918. http://hdl.handle.net/11427/34408