Zobrazeno 1 - 10
of 171
pro vyhledávání: '"Rørdam, Mikael"'
Autor:
Blackadar, Bruce, Rørdam, Mikael
We give a simple and elementary proof that the tracial state space of a unital C$^*$-algebra is a Choquet simplex, using the center-valued trace on a finite von Neumann algebra.
Comment: 12 pages. Two extra references added, and last section org
Comment: 12 pages. Two extra references added, and last section org
Externí odkaz:
http://arxiv.org/abs/2409.09644
Autor:
Milhøj, Henning O., Rørdam, Mikael
This paper presents a survey of results on traces and quasitraces on C$^*$-algebras, and it provides some new results on traces on ultrapowers and on the existence of faithful traces. As for the former, we exhibit a sequence of traceless simple, sepa
Externí odkaz:
http://arxiv.org/abs/2309.17412
Autor:
Rørdam, Mikael
In his study of the relative Dixmier property for inclusions of von Neumann algebras and of $C^*$-algebras, Popa considered a certain property of automorphisms on $C^*$-algebras, that we here call the strong averaging property. In this note we charac
Externí odkaz:
http://arxiv.org/abs/2211.03669
Autor:
Echterhoff, Siegfried, Rørdam, Mikael
We examine inclusions of $C^*$-algebras of the form $A^H \subseteq A \rtimes_{r} G$, where $G$ and $H$ are groups acting on a unital simple $C^*$-algebra $A$ by outer automorphisms and $H$ is finite. It follows from a theorem of Izumi that $A^H \subs
Externí odkaz:
http://arxiv.org/abs/2108.08832
Autor:
Rørdam, Mikael
The literature contains interesting examples of inclusions of simple C$^*$-algebras with the property that all intermediate C$^*$-algebras likewise are simple. In this article we take up a systematic study of such inclusions, which we refer to as bei
Externí odkaz:
http://arxiv.org/abs/2105.11899
Autor:
Musat, Magdalena, Rørdam, Mikael
We relate factorizable quantum channels on $M_n$, for $n \ge 2$, via their Choi matrix, to certain correlation matrices, which, in turn, are shown to be parametrized by traces on the unital free product $M_n * M_n$. Factorizable maps that admit a fin
Externí odkaz:
http://arxiv.org/abs/1903.10182
Autor:
Musat, Magdalena, Rørdam, Mikael
We show that there exist factorizable quantum channels in each dimension $\ge 11$ which do not admit a factorization through any finite dimensional von Neumann algebra, and do require ancillas of type II$_1$, thus witnessing new infinite-dimensional
Externí odkaz:
http://arxiv.org/abs/1806.10242
Autor:
Rordam, Mikael
Nicolas Monod introduced the class of groups with the fixed-point property for cones, characterized by always admitting a non-zero fixed point whenever acting (suitably) on proper weakly complete cones. He proved that his class of groups contains the
Externí odkaz:
http://arxiv.org/abs/1803.11075
Autor:
Rordam, Mikael
Just-infinite C*-algebras, i.e., infinite dimensional C*-algebras, whose proper quotients are finite dimensional, were investigated in [Grigorchuk-Musat-Rordam, 2016]. One particular example of a just-infinite residually finite dimensional AF-algebra
Externí odkaz:
http://arxiv.org/abs/1705.02818
Autor:
Farah, Ilijas, Rørdam, Mikael
We show that the class of C*-algebras with stable rank greater than a given positive integer is axiomatizable in logic of metric structures. As a consequence we show that the stable rank is continuous with respect to forming ultrapowers of C*-algebra
Externí odkaz:
http://arxiv.org/abs/1611.08462