Deformation of finite morphisms and smoothing of ropes

In this paper we prove that most ropes of arbitrary multiplicity supported on smooth curves can be smoothed. By a rope being smoothable we mean that the rope is the flat limit of a family of smooth, irreducible curves. To construct a smoothing, we connect, on the one hand, deformations of a finite m...

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Detalhes bibliográficos
Autores: Gallego Rodrigo, Francisco Javier, González Andrés, Miguel, Purnaprajna, Bangere P.
Tipo de documento: artigo
Data de publicação:2008
País:España
Recursos:Universidad Complutense de Madrid (UCM)
Repositório:Docta Complutense
Idioma:inglês
OAI Identifier:oai:docta.ucm.es:20.500.14352/49667
Acesso em linha:https://hdl.handle.net/20.500.14352/49667
Access Level:Acceso aberto
Palavra-chave:512.7
Degenerations of curves
Multiple structures
Deformations of morphisms
Geometria algebraica
1201.01 Geometría Algebraica
Descrição
Resumo:In this paper we prove that most ropes of arbitrary multiplicity supported on smooth curves can be smoothed. By a rope being smoothable we mean that the rope is the flat limit of a family of smooth, irreducible curves. To construct a smoothing, we connect, on the one hand, deformations of a finite morphism to projective space and, on the other hand, morphisms from a rope to projective space. We also prove a general result of independent interest, namely that finite covers onto smooth irreducible curves embedded in projective space can be deformed to a family of 1 : 1 maps. We apply our general theory to prove the smoothing of ropes of multiplicity 3 on P1. Even though this paper focuses on ropes of dimension 1, our method yields a general approach to deal with the smoothing of ropes of higher dimension.