{"title":"在非交换轨道上跟踪射影模","authors":"Sayan Chakraborty","doi":"10.4171/jncg/487","DOIUrl":null,"url":null,"abstract":"For an action of a finite cyclic group $F$ on an $n$-dimensional noncommutative torus $A_\\theta,$ we give sufficient conditions when the fundamental projective modules over $A_\\theta$, which determine the range of the canonical trace on $A_\\theta,$ extend to projective modules over the crossed product C*-algebra $A_\\theta \\rtimes F.$ Our results allow us to understand the range of the canonical trace on $A_\\theta \\rtimes F$, and determine it completely for several examples including the crossed products of 2-dimensional noncommutative tori with finite cyclic groups and the flip action of $\\mathbb{Z}_2$ on any $n$-dimensional noncommutative torus. As an application, for the flip action of $\\mathbb{Z}_2$ on a simple $n$-dimensional torus $A_\\theta$, we determine the Morita equivalence class of $A_\\theta \\rtimes \\mathbb{Z}_2,$ in terms of the Morita equivalence class of $A_\\theta.$","PeriodicalId":54780,"journal":{"name":"Journal of Noncommutative Geometry","volume":" ","pages":""},"PeriodicalIF":0.7000,"publicationDate":"2021-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":"{\"title\":\"Tracing projective modules over noncommutative orbifolds\",\"authors\":\"Sayan Chakraborty\",\"doi\":\"10.4171/jncg/487\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"For an action of a finite cyclic group $F$ on an $n$-dimensional noncommutative torus $A_\\\\theta,$ we give sufficient conditions when the fundamental projective modules over $A_\\\\theta$, which determine the range of the canonical trace on $A_\\\\theta,$ extend to projective modules over the crossed product C*-algebra $A_\\\\theta \\\\rtimes F.$ Our results allow us to understand the range of the canonical trace on $A_\\\\theta \\\\rtimes F$, and determine it completely for several examples including the crossed products of 2-dimensional noncommutative tori with finite cyclic groups and the flip action of $\\\\mathbb{Z}_2$ on any $n$-dimensional noncommutative torus. As an application, for the flip action of $\\\\mathbb{Z}_2$ on a simple $n$-dimensional torus $A_\\\\theta$, we determine the Morita equivalence class of $A_\\\\theta \\\\rtimes \\\\mathbb{Z}_2,$ in terms of the Morita equivalence class of $A_\\\\theta.$\",\"PeriodicalId\":54780,\"journal\":{\"name\":\"Journal of Noncommutative Geometry\",\"volume\":\" \",\"pages\":\"\"},\"PeriodicalIF\":0.7000,\"publicationDate\":\"2021-02-15\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"1\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Noncommutative Geometry\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://doi.org/10.4171/jncg/487\",\"RegionNum\":2,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Noncommutative Geometry","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.4171/jncg/487","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
Tracing projective modules over noncommutative orbifolds
For an action of a finite cyclic group $F$ on an $n$-dimensional noncommutative torus $A_\theta,$ we give sufficient conditions when the fundamental projective modules over $A_\theta$, which determine the range of the canonical trace on $A_\theta,$ extend to projective modules over the crossed product C*-algebra $A_\theta \rtimes F.$ Our results allow us to understand the range of the canonical trace on $A_\theta \rtimes F$, and determine it completely for several examples including the crossed products of 2-dimensional noncommutative tori with finite cyclic groups and the flip action of $\mathbb{Z}_2$ on any $n$-dimensional noncommutative torus. As an application, for the flip action of $\mathbb{Z}_2$ on a simple $n$-dimensional torus $A_\theta$, we determine the Morita equivalence class of $A_\theta \rtimes \mathbb{Z}_2,$ in terms of the Morita equivalence class of $A_\theta.$
期刊介绍:
The Journal of Noncommutative Geometry covers the noncommutative world in all its aspects. It is devoted to publication of research articles which represent major advances in the area of noncommutative geometry and its applications to other fields of mathematics and theoretical physics. Topics covered include in particular:
Hochschild and cyclic cohomology
K-theory and index theory
Measure theory and topology of noncommutative spaces, operator algebras
Spectral geometry of noncommutative spaces
Noncommutative algebraic geometry
Hopf algebras and quantum groups
Foliations, groupoids, stacks, gerbes
Deformations and quantization
Noncommutative spaces in number theory and arithmetic geometry
Noncommutative geometry in physics: QFT, renormalization, gauge theory, string theory, gravity, mirror symmetry, solid state physics, statistical mechanics.