Advances in Mathematics ( IF 1.5 ) Pub Date : 2021-06-02 , DOI: 10.1016/j.aim.2021.107798 Ilan Hirshberg , Jianchao Wu
We show that for any locally compact Hausdorff space Y with finite covering dimension and for any continuous flow , the resulting crossed product -algebra has finite nuclear dimension. This generalizes previous results for free flows, where this was proved using Rokhlin dimension techniques. As an application, we obtain bounds for the nuclear dimension of -algebras associated to one-dimensional orientable foliations. This result is analogous to the one we obtained earlier for non-free actions of . Some novel techniques in our proof include the use of a conditional expectation constructed from the inclusion of a clopen subgroupoid, as well as the introduction of what we call fiberwise groupoid coverings that help us build a link between foliation -algebras and crossed products.
中文翻译:
与拓扑流和可定向线叶理相关的C ⁎ -代数的核维数
我们证明了对于任何具有有限覆盖维数的局部紧致 Hausdorff 空间Y和任何连续流,得到的交叉产品 -代数 具有有限的核维数。这概括了先前的自由流动结果,其中使用 Rokhlin 维数技术证明了这一点。作为一个应用,我们获得了核维数的界限-与一维可定向叶面相关的代数。这个结果类似于我们之前为非自由动作获得的结果. 我们证明中的一些新技术包括使用由包含 cloopen subgroupoid 构建的条件期望,以及引入我们所谓的 Fiberwise groupoid 覆盖,帮助我们在 foliation 之间建立联系-代数和交叉产品。