On the slope of fibred surfaces

We give an asymptotically sharp lower bound for the slope $\lambda (f)$ of a fibration $f:S\longrightarrow B$, where $S$ is a surface and $B$ is a curve, if there exists an involution on the general fibre $F$ of $f$. We also construct a new lower bound of $\lambda (f)$ depending increasingly on the...

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Detalhes bibliográficos
Autores: Barja Yáñez, Miguel Ángel|||0000-0003-2822-3938, Zucconi, Franco
Tipo de documento: artigo
Data de publicação:2000
País:España
Recursos:Universitat Politècnica de Catalunya (UPC)
Repositório:UPCommons. Portal del coneixement obert de la UPC
Idioma:inglês
OAI Identifier:oai:upcommons.upc.edu:2117/815
Acesso em linha:https://hdl.handle.net/2117/815
Access Level:Acceso aberto
Palavra-chave:Geometry, Algebraic
Surfaces
fibred surfaces
Fibrats (Matemàtica)
Superfícies
Varietats (Matemàtica)
Classificació AMS::14 Algebraic geometry::14D Families, fibrations
Classificació AMS::14 Algebraic geometry::14J Surfaces and higher-dimensional varieties
Descrição
Resumo:We give an asymptotically sharp lower bound for the slope $\lambda (f)$ of a fibration $f:S\longrightarrow B$, where $S$ is a surface and $B$ is a curve, if there exists an involution on the general fibre $F$ of $f$. We also construct a new lower bound of $\lambda (f)$ depending increasingly on the irregularity of $S$; as an application of this new bound we have a criteria to control the existence of other fibrations on $S$.