On the degree of irrationality of low genus $K3$ surfaces

Fuente: arXiv
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Main Authors: Moretti, Federico, Rojas, Andrés
Format: Preprint
Published: 2024
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author Moretti, Federico
Rojas, Andrés
author_facet Moretti, Federico
Rojas, Andrés
contents Given a general polarized $K3$ surface $S\subset \mathbb P^g$ of genus $g\le 14$, we study projections $S\hookrightarrow \mathbb P^g\dashrightarrow \mathbb P^2$ of minimal degree and their variational structure. In particular, we prove that the degree of irrationality of all such surfaces is at most $4$, and that for $g=7,8,9,11$ there are no rational maps $S\dashrightarrow \mathbb P^2$ of degree $3$ induced by the primitive linear system. Our methods combine vector bundle techniques à la Lazarsfeld with derived category tools, and also make use of the rich theory of singular curves on $K3$ surfaces.
format Preprint
id arxiv_https___arxiv_org_abs_2401_03821
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On the degree of irrationality of low genus $K3$ surfaces
Moretti, Federico
Rojas, Andrés
Algebraic Geometry
14E05, 14F08, 14J28
Given a general polarized $K3$ surface $S\subset \mathbb P^g$ of genus $g\le 14$, we study projections $S\hookrightarrow \mathbb P^g\dashrightarrow \mathbb P^2$ of minimal degree and their variational structure. In particular, we prove that the degree of irrationality of all such surfaces is at most $4$, and that for $g=7,8,9,11$ there are no rational maps $S\dashrightarrow \mathbb P^2$ of degree $3$ induced by the primitive linear system. Our methods combine vector bundle techniques à la Lazarsfeld with derived category tools, and also make use of the rich theory of singular curves on $K3$ surfaces.
title On the degree of irrationality of low genus $K3$ surfaces
topic Algebraic Geometry
14E05, 14F08, 14J28
url https://arxiv.org/abs/2401.03821