The classification problem for von Neumann factors

We prove that it is not possible to classify separable von Neumann factors of types II1, II∞ or IIIλ, 0 λ 1, up to isomorphism by a Borel measurable assignment of “countable structures” as invariants. In particular the isomorphism relation of type II1 factors is not smooth. We also prove that the is...

ver descrição completa

Detalhes bibliográficos
Autores: Sasyk, Roman, Törnquist, Asger
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2008
País:Argentina
Recursos:Consejo Nacional de Investigaciones Científicas y Técnicas
Repositorio:CONICET Digital (CONICET)
Idioma:inglés
OAI Identifier:oai:ri.conicet.gov.ar:11336/19477
Acesso em linha:http://hdl.handle.net/11336/19477
Access Level:acceso abierto
Palavra-chave:von Neumann algebras
Classification
Borel reducibility
Turbulence
https://purl.org/becyt/ford/1.1
https://purl.org/becyt/ford/1
Descrição
Resumo:We prove that it is not possible to classify separable von Neumann factors of types II1, II∞ or IIIλ, 0 λ 1, up to isomorphism by a Borel measurable assignment of “countable structures” as invariants. In particular the isomorphism relation of type II1 factors is not smooth. We also prove that the isomorphism relation for von Neumann II1 factors is analytic, but is not Borel.