Zobrazeno 1 - 10
of 138
pro vyhledávání: '"ROBERT, LEONEL"'
We call a continuous path of polygons decreasing if the convex hulls of the polygons form a decreasing family of sets. For an arbitrary polygon of more than three vertices, we characterize the polygons contained in it that can be reached by a decreas
Externí odkaz:
http://arxiv.org/abs/2402.12643
Autor:
Robert, Leonel
The aim of this note is to advertise a class of simple C*-algebras which includes noteworthy examples such as the Jiang-Su C*-algebra, the infinite dimensional UHF C*-algebras, the reduced group C*-algebra of the free group in infinitely many generat
Externí odkaz:
http://arxiv.org/abs/2309.14188
We obtain partial affirmative answers to the question whether isomorphism of the unitary groups of two C*-algebras, either as topological groups or as discrete groups, implies isomorphism of the C*-algebras as real C*-algebras.
Externí odkaz:
http://arxiv.org/abs/2306.15825
Using Cuntz semigroup techniques, we characterize when limit traces are dense in the space of all traces on a free ultrapower of a C*-algebra. More generally, we consider density of limit quasitraces on ultraproducts of C*-algebras. Quite unexpectedl
Externí odkaz:
http://arxiv.org/abs/2303.01929
Autor:
Chand, Abhinav, Robert, Leonel
We show that the commutator subgroup of the group of unitaries connected to the identity in a simple unital C*-algebra is simple modulo its center. We then go on to investigate the role of regularity properties in the structure of the special unitary
Externí odkaz:
http://arxiv.org/abs/2108.09796
We study variants of the Dixmier property that apply to elements of a unital C*-algebra, rather than to the C*-algebra itself. By a Dixmier element in a C*-algebra we understand one that can be averaged into a central element by means of a sequence o
Externí odkaz:
http://arxiv.org/abs/2106.00098
Autor:
Robert, Leonel
We obtain a characterization of the unital C*-algebras with the property that every element is a limit of products of positive elements, thereby answering a question of Murphy and Phillips.
Comment: 5 pages
Comment: 5 pages
Externí odkaz:
http://arxiv.org/abs/2103.15238
Publikováno v:
In Journal of Functional Analysis 15 April 2024 286(8)
We show that if every element a vector subspace of a C*-algebra can be averaged to zero by means of unitary mixing operators, then all the elements of the subspace can be simultaneously averaged to zero by a net of unitary mixing operators. Moreover,
Externí odkaz:
http://arxiv.org/abs/2012.02830
Autor:
Moodie, Mark, Robert, Leonel
We characterize the topological non-cancellative cones that are expressible as projective limits of finite powers of $[0,\infty]$. These are also the cones of lower semicontinuous extended-valued traces on AF C*-algebras. Our main result may be regar
Externí odkaz:
http://arxiv.org/abs/2009.09033