The Hanna Neumann conjecture for surface groups

The Hanna Neumann conjecture is a statement about the rank of the intersection of two finitely generated subgroups of a free group. The conjecture was posed by Hanna Neumann in 1957. In 2011, a strengthened version of the conjecture was proved independently by Joel Friedman and by Igor Mineyev. In t...

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Detalles Bibliográficos
Autores: Antolín Pichel, Yago, Jaikin-Zapirain, Andrei
Tipo de recurso: artículo
Fecha de publicación:2022
País:España
Institución:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/71666
Acceso en línea:https://hdl.handle.net/20.500.14352/71666
Access Level:acceso abierto
Palabra clave:512.54
Surface groups
Limit groups
L2-Betti numbers
The Hanna Neumann conjecture
Lück's approximation
Grupos (Matemáticas)
Descripción
Sumario:The Hanna Neumann conjecture is a statement about the rank of the intersection of two finitely generated subgroups of a free group. The conjecture was posed by Hanna Neumann in 1957. In 2011, a strengthened version of the conjecture was proved independently by Joel Friedman and by Igor Mineyev. In this paper we show that the strengthened Hanna Neumann conjecture holds not only in free groups but also in non-solvable surface groups. In addition, we show that a retract in a free group and in a surface group is inert. This implies the Dicks–Ventura inertia conjecture for free and surface groups.