The obstruction to excision in K-theory and in cyclic homology
Let f: A → B be a ring homomorphism of not necessarily unital rings and I A an ideal which is mapped by f isomorphically to an ideal of B. The obstruction to excision in K-theory is the failure of the map between relative K-groups K *(A:I)→K *(B:f(I)) to be an isomorphism; it is measured by the bire...
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2006 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/151169 |
| Acceso en línea: | http://hdl.handle.net/11336/151169 |
| Access Level: | acceso abierto |
| Palabra clave: | RING HOMOMORPHISM UNITAL RING CHERN CHARACTER CYCLIC HOMOLOGY NEGATIVE CYCLIC HOMOLOGY https://purl.org/becyt/ford/1.1 https://purl.org/becyt/ford/1 |
| Sumario: | Let f: A → B be a ring homomorphism of not necessarily unital rings and I A an ideal which is mapped by f isomorphically to an ideal of B. The obstruction to excision in K-theory is the failure of the map between relative K-groups K *(A:I)→K *(B:f(I)) to be an isomorphism; it is measured by the birelative groups K *(A,B:I) . Similarly the groups HN *(A,B:I) measure the obstruction to excision in negative cyclic homology. We show that the rational Jones-Goodwillie Chern character induces an isomorphism ch *:K *(A,B:I)⊗ ℚ →simHN * A ⊗ℚ,B ⊗ℚ:I ⊗ℚ. |
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