A note on the Severi problem for toric surfaces

Fuente: arXiv
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Main Authors: Lang, Lionel, Tyomkin, Ilya
Format: Preprint
Published: 2020
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_version_ 1866915120905453568
author Lang, Lionel
Tyomkin, Ilya
author_facet Lang, Lionel
Tyomkin, Ilya
contents In this note, we make a step towards the classification of toric surfaces admitting reducible Severi varieties. We generalize the results of [Lan19, Tyo13, Tyo14], and provide two families of toric surfaces admitting reducible Severi varieties. The first family is general, and is obtained by a quotient construction. The second family is exceptional, and corresponds to certain narrow polygons, which we call kites. We introduce two types of invariants that distinguish between the components of the Severi varieties, and allow us to provide lower bounds on the numbers of the components. The sharpness of the bounds is verified in some cases, and is expected to hold in general for ample enough linear systems. In the appendix, we establish a connection between the Severi problem and the topological classification of univariate polynomials.
format Preprint
id arxiv_https___arxiv_org_abs_2007_11550
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle A note on the Severi problem for toric surfaces
Lang, Lionel
Tyomkin, Ilya
Algebraic Geometry
14H10, 14M25, 14T90
In this note, we make a step towards the classification of toric surfaces admitting reducible Severi varieties. We generalize the results of [Lan19, Tyo13, Tyo14], and provide two families of toric surfaces admitting reducible Severi varieties. The first family is general, and is obtained by a quotient construction. The second family is exceptional, and corresponds to certain narrow polygons, which we call kites. We introduce two types of invariants that distinguish between the components of the Severi varieties, and allow us to provide lower bounds on the numbers of the components. The sharpness of the bounds is verified in some cases, and is expected to hold in general for ample enough linear systems. In the appendix, we establish a connection between the Severi problem and the topological classification of univariate polynomials.
title A note on the Severi problem for toric surfaces
topic Algebraic Geometry
14H10, 14M25, 14T90
url https://arxiv.org/abs/2007.11550