{"title":"Realizations of rigid C*-tensor categories as bimodules over GJS C*-algebras","authors":"Michael Hartglass, Roberto Hernández Palomares","doi":"10.1063/5.0015294","DOIUrl":"https://doi.org/10.1063/5.0015294","url":null,"abstract":"Given an arbitrary countably generated rigid C*-tensor category, we construct a fully-faithful bi-involutive strong monoidal functor onto a subcategory of finitely generated projective bimodules over a simple, exact, separable, unital C*-algebra with unique trace. The C*-algebras involved are built from the category using the GJS-construction introduced in arXiv:0911.4728 and further studied in arXiv:1208.5505 and arXiv:1401.2486. Out of this category of Hilbert C*-bimodules, we construct a fully-faithful bi-involutive strong monoidal functor into the category of bi-finite spherical bimodules over an interpolated free group factor. The composite of these two functors recovers the functor constructed in arXiv:1208.5505","PeriodicalId":351745,"journal":{"name":"arXiv: Operator Algebras","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134488213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Quantum E(2) groups for complex deformation parameters","authors":"Atibur Rahaman, Sutanu Roy","doi":"10.1142/S0129055X21500215","DOIUrl":"https://doi.org/10.1142/S0129055X21500215","url":null,"abstract":"We construct a family of $q$ deformations of $E(2)$ groups for nonzero complex parameters $|q|<1$ as locally compact braided quantum groups over the circle group $mathbb{T}$ with respect to the unitary $R$-matrix $chicolonmathbb{Z}timesmathbb{Z}tomathbb{T}$ defined by $chi(m,n):=(zeta)^{mn}$, where $zeta:= q/bar{q}$. For real $0<|q|<1$, the deformation coincides with Woronowicz's $E_{q}(2)$ groups.","PeriodicalId":351745,"journal":{"name":"arXiv: Operator Algebras","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116960369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Maximality and finiteness of type 1 subdiagonal algebras","authors":"Guoxing Ji","doi":"10.1090/proc/15287","DOIUrl":"https://doi.org/10.1090/proc/15287","url":null,"abstract":"Let $mathfrak A$ be a type 1 subdiagonal algebra in a $sigma$-finite von Neumann algebra $mathcal M$ with respect to a faithful normal conditional expectation $Phi$. We give necessary and sufficient conditions for which $mathfrak A$ is maximal among the $sigma$-weakly closed subalgebras of $mathcal M$. In addition, we show that a type 1 subdiagonal algebra in a finite von Neumann algebra is automatically finite which gives a positive answer of Arveson's finiteness problem in 1967 in type 1 case.","PeriodicalId":351745,"journal":{"name":"arXiv: Operator Algebras","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125330620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A torsion-free algebraically $mathrm{C}^*$-unique group","authors":"Eduardo Scarparo","doi":"10.1216/RMJ.2020.50.1813","DOIUrl":"https://doi.org/10.1216/RMJ.2020.50.1813","url":null,"abstract":"Let $p$ and $q$ be multiplicatively independent integers. We show that the complex group ring of $mathbb{Z}[frac{1}{pq}]rtimesmathbb{Z}^2$ admits a unique $mathrm{C}^*$-norm. The proof uses a characterization, due to Furstenberg, of closed $times p-$ and $times q-$invariant subsets of $mathbb{T}$.","PeriodicalId":351745,"journal":{"name":"arXiv: Operator Algebras","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122012505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Residual finiteness for central pushouts","authors":"A. Chirvasitu","doi":"10.1090/proc/15368","DOIUrl":"https://doi.org/10.1090/proc/15368","url":null,"abstract":"We prove that pushouts $A*_CB$ of residually finite-dimensional (RFD) $C^*$-algebras over central subalgebras are always residually finite-dimensional provided the fibers $A_p$ and $B_p$, $pin mathrm{spec}~C$ are RFD, recovering and generalizing results by Korchagin and Courtney-Shulman. This then allows us to prove that certain central pushouts of amenable groups have RFD group $C^*$-algebras. Along the way, we discuss the problem of when, given a central group embedding $Hle G$, the resulting $C^*$-algebra morphism is a continuous field: this is always the case for amenable $G$ but not in general.","PeriodicalId":351745,"journal":{"name":"arXiv: Operator Algebras","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115551604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"L\u0000 2-Betti Numbers of C*-Tensor Categories Associated with Totally Disconnected Groups","authors":"Matthias Valvekens","doi":"10.1093/IMRN/RNAB066","DOIUrl":"https://doi.org/10.1093/IMRN/RNAB066","url":null,"abstract":"We prove that the $L^2$-Betti numbers of a rigid $C^*$-tensor category vanish in the presence of an almost-normal subcategory with vanishing $L^2$-Betti numbers, generalising a result of Bader, Furman and Sauer. We apply this criterion to show that the categories constructed from totally disconnected groups by Arano and Vaes have vanishing $L^2$-Betti numbers. Given an almost-normal inclusion of discrete groups $Lambda<Gamma$, with $Gamma$ acting on a type $mathrm{II}_1$ factor $P$ by outer automorphisms, we relate the cohomology theory of the quasi-regular inclusion $PrtimesLambdasubset PrtimesGamma$ to that of the Schlichting completion $G$ of $Lambda<Gamma$. If $Lambda<Gamma$ is unimodular, this correspondence allows us to prove that the $L^2$-Betti numbers of $PrtimesLambdasubset PrtimesGamma$ are equal to those of $G$.","PeriodicalId":351745,"journal":{"name":"arXiv: Operator Algebras","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124067094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}