当前期刊: Journal of Noncommutative Geometry Go to current issue    加入关注   
显示样式:        排序: IF: - GO 导出
我的关注
我的收藏
您暂时未登录!
登录
  • Bounds for the rank of the finite part of operator $K$-theory
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-06-30
    Süleyman Kağan Samurkaş

    We derive a lower and an upper bound for the rank of the finite part of operator $K$-theory groups of maximal and reduced $C^*$-algebras of finitely generated groups. The lower bound is based on the amount of polynomially growing conjugacy classes of finite order elements in the group. The upper bound is based on the amount of torsion elements in the group. We use the lower bound to give lower bounds

    更新日期:2020-07-30
  • Additivity of higher rho invariant for the topological structure group from a differential point of view
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-05-28
    Baojie Jiang; Hongzhi Liu

    In [16], Weinberger, Xie, and Yu proved that higher rho invariant associated to homotopy equivalence defines a group homomorphism from the topological structure group to the analytic structure group, $K$-theory of certain geometric $C^*$-algebras, by piecewise-linear approach. In this paper, we adapt part of Weinberger, Xie, and Yu’s work, to give a differential geometry theoretic proof of the additivity

    更新日期:2020-07-30
  • Descent of Hilbert $C$*-modules
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-06-25
    Tyrone Crisp

    Let $F$ be a right Hilbert $C$*-module over a $C$*-algebra $B$, and suppose that $F$ is equipped with a left action, by compact operators, of a second $C$*-algebra $A$. Tensor product with $F$ gives a functor from Hilbert $C$*-modules over $A$ to Hilbert $C$*-modules over $B$. We prove that under certain conditions (which are always satisfied if, for instance, $A$ is nuclear), the image of this functor

    更新日期:2020-07-30
  • $A_{\infty}$-coderivations and the Gerstenhaber bracket on Hochschild cohomology
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-06-26
    Cris Negron; Yury Volkov; Sarah Witherspoon

    We show that Hochschild cohomology of an algebra over a field is a space of infinity coderivations on an arbitrary projective bimodule resolution of the algebra. The Gerstenhaber bracket is the graded commutator of infinity coderivations. We thus generalize, to an arbitrary resolution, Stasheff’s realization of the Gerstenhaber bracket on Hochschild cohomology as the graded commutator of coderivations

    更新日期:2020-07-30
  • Property (T), property (F) and residual finiteness for discrete quantum groups
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-07-02
    Angshuman Bhattacharya; Michael Brannan; Alexandru Chirvasitu; Shuzhou Wang

    We investigate connections between various rigidity and softness properties for discrete quantum groups. After introducing a notion of residual finiteness, we show that it implies the Kirchberg factorization property for the discrete quantum group in question. We also prove the analogue of Kirchberg’s theorem, to the effect that conversely, the factorization property and property (T) jointly imply

    更新日期:2020-07-30
  • Tannaka duality for enhanced triangulated categories I: reconstruction
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-07-13
    Jonathan P. Pridham

    We develop Tannaka duality theory for dg categories. To any dg functor from a dg category $\mathcal A$ to finite-dimensional complexes, we associate a dg coalgebra $C$ via a Hochschild homology construction. When the dg functor is faithful, this gives a quasi-equivalence between the derived dg categories of $\mathcal A$-modules and of $C$-comodules. When $\mathcal A$ is Morita fibrant (i.e. an idempotent-complete

    更新日期:2020-07-30
  • Bivariant K-theory of generalized Weyl algebras
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-07-19
    Julio Gutiérrez; Christian Valqui

    We compute the isomorphism class in $\mathfrak{KK}^{\mathrm {alg}}$ of all noncommutative generalized Weyl algebras $A=\mathbb C[h](\sigma, P)$,where $\sigma(h)=qh+h_0$ is an automorphism of $\mathcal C[h]$, except when $q\neq 1$ is a root of unity. In particular, we compute the isomorphism class in $\mathfrak{KK}^{\mathrm {alg}}$ of the quantum Weyl algebra, the primitive factors $B_{\lambda}$ of

    更新日期:2020-07-30
  • The nodal cubic and quantum groups at roots of unity
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-07-21
    Ulrich Krähmer; Manuel Martins

    In a recent article, the coordinate ring of the nodal cubic was given the structure of a quantum homogeneous space. Here the corresponding coalgebra Galois extension is expressed in terms of quantum groups at roots of unity, and is shown to be cleft. Furthermore, the minimal quotient extensions are determined.

    更新日期:2020-07-30
  • Almost commutative $Q$-algebras and derived brackets
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-07-13
    Andrew J. Bruce

    We introduce the notion of almost commutative $Q$-algebras and demonstrate how the derived bracket formalism of Kosmann–Schwarzbach generalises to this setting. In particular, we construct ‘almost commutative Lie algebroids’ following Vaıntrob’s $Q$-manifold understanding of classical Lie algebroids. We show that the basic tenets of the theory of Lie algebroids carry over verbatim to the almost commutative

    更新日期:2020-07-30
  • A Chern–Weil formula for the Chern character of a perfect curved module
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-07-29
    Michael K. Brown; Mark E. Walker

    Let $k$ be a field of characteristic 0 and $\mathcal{A}$ a curved $k$-algebra. We obtain a Chern–Weil-type formula for the Chern character of a perfect $\mathcal{A}$-module taking values in $HN^{II}_0(\mathcal{A})$, the negative cyclic homology of the second kind associated to $\mathcal{A}$, when $\mathcal{A}$ satisfies a certain smoothness condition.

    更新日期:2020-07-30
  • Embedding of the derived Brauer group into the secondary $K$-theory ring
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-07-21
    Gonçalo Tabuada

    In this note, making use of the recent theory of noncommutative motives, we prove that the canonical map from the derived Brauer group to the secondary Grothendieck ring has the following injectivity properties: in the case of a regular integral quasi-compact quasi-separated scheme, it is injective; in the case of an integral normal Noetherian scheme with a single isolated singularity, it distinguishes

    更新日期:2020-07-30
  • On the twisted tensor product of small dg categories
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-07-29
    Boris Shoikhet

    Given two small dg categories $C,D$, defined over a field, we introduce their (non-symmetric) twisted tensor product $C\sotimes D$. We show that $-\sotimes D$ is left adjoint to the functor $\mathcal {Coh}(D,-)$, where $\mathcal {Coh}(D,E)$ is the dg category of dg functors $D\to E$ and their coherent natural transformations. This adjunction holds in the category of small dg categories (not in the

    更新日期:2020-07-30
  • The Higson–Roe sequence for étale groupoids. I. Dual algebras and compatibility with the BC map
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-05-14
    Moulay-Tahar Benameur; Indrava Roy

    We introduce the dual Roe algebras for proper étale groupoid actions and deduce the expected Higson–Roe short exact sequence. When the action is co-compact, we show that the Roe $C^*$-ideal of locally compact operators is Morita equivalent to the reduced $C^*$-algebra of our groupoid, and we further identify the boundary map of the associated periodic six-term exact sequence with the Baum–Connes map

    更新日期:2020-07-20
  • Non-commutative crepant resolutions for some toric singularities. II
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-05-18
    Špela Špenko; Michel Van den Bergh

    Using the theory of dimer models Broomhead proved that every 3-dimensional Gorenstein affine toric variety Spec $R$ admits a toric non-commutative crepant resolution (NCCR). We give an alternative proof of this result by constructing a tilting bundle on a (stacky) crepant resolution of Spec $R$ using standard toric methods. Our proof does not use dimer models.

    更新日期:2020-07-20
  • Hecke operators in $KK$-theory and the $K$-homology of Bianchi groups
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-05-14
    Bram Mesland; Mehmet Haluk Şengün

    Let $\Gamma$ be a torsion-free arithmetic group acting on its associated global symmetric space $X$. Assume that $X$ is of non-compact type and let $\Gamma$ act on the geodesic boundary $\partial X$ of $X$. Via general constructions in $KK$-theory, we endow the $K$-groups of the arithmetic manifold $X / \Gamma$, of the reduced group $C^*$-algebra $C^*_r(\Gamma)$ and of the boundary crossed product

    更新日期:2020-07-20
  • Differential calculus over double Lie algebroids
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-05-25
    Sophie Chemla

    M. Van den Bergh [20] defined the notion of a double Lie algebroid and showed that a double quasi-Poisson algebra gives rise to a double Lie algebroid.We give new examples of double Lie algebroids and develop a differential calculus in that context. We recover the non commutative Karoubi–de Rham complex [7, 9] and the double Poisson–Lichnerowicz cohomology [16] as particular cases of our construction

    更新日期:2020-07-20
  • Annular representations of free product categories
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-05-14
    Shamindra Kumar Ghosh; Corey Jones; B. Madhav Reddy

    We provide a description of the annular representation category of the free product of two rigid C*-tensor categories.

    更新日期:2020-07-20
  • Simple stably projectionless C*-algebras with generalized tracial rank one
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-05-28
    George A. Elliott; Guihua Gong; Huaxin Lin; Zhuang Niu

    We study a class of stably projectionless simple C*-algebras which may be viewed as having generalized tracial rank one in analogy with the unital case. A number of structural questions concerning these simple C*-algebras are studied, pertinent to the classification of separable stably projectionless simple amenable Jiang–Su stable C*-algebras.

    更新日期:2020-07-20
  • Frobenius degenerations of preprojective algebras
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-05-27
    Daniel Kaplan

    In this paper, we study a preprojective algebra for quivers decorated with $k$-algebras and bimodules, which generalizes work of Gabriel for ordinary quivers, work of Dlab and Ringel for$ $k-species, and recent work of de Thanhoffer de Völcsey and Presotto, which has recently appeared from a different perspective in work of Külshammer. As for undecorated quivers, we show that its moduli space of representations

    更新日期:2020-07-20
  • Quantum groups with projection and extensions of locally compact quantum groups
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-04-30
    Paweł Kasprzak; Piotr M. Sołtan

    The main result of the paper is the characterization of those locally compact quantum groups with projection, i.e. non-commutative analogs of semidirect products, which are extensions as defined by L. Vainerman and S. Vaes. It turns out that quantum groups with projection are usually not extensions.We discuss several examples including the quantum $\mathrm{U}_q(2)$. The major tool used to obtain these

    更新日期:2020-04-30
  • The spectral localizer for even index pairings
    J. Noncommut. Geom. (IF 0.727) Pub Date : 2020-02-11
    Terry A. Loring; Hermann Schulz-Baldes

    Even index pairings are integer-valued homotopy invariants combining an even Fredholm module with a $K_0$-class specified by a projection. Numerous classical examples are known from differential and non-commutative geometry and physics. Here it is shown how to construct a finite-dimensional self-adjoint and invertible matrix, called the spectral localizer, such that half its signature is equal to the

    更新日期:2020-02-11
Contents have been reproduced by permission of the publishers.
导出
全部期刊列表>>
欢迎访问IOP中国网站
自然职场线上招聘会
GIANT
产业、创新与基础设施
自然科研线上培训服务
材料学研究精选
胸腔和胸部成像专题
屿渡论文,编辑服务
何川
苏昭铭
陈刚
姜涛
李闯创
李刚
北大
隐藏1h前已浏览文章
课题组网站
新版X-MOL期刊搜索和高级搜索功能介绍
ACS材料视界
天合科研
x-mol收录
上海纽约大学
陈芬儿
厦门大学
何振宇
史大永
吉林大学
卓春祥
张昊
杨中悦
试剂库存
down
wechat
bug