English

Absorbing representations with respect to closed operator convex cones

Operator Algebras 2015-10-19 v2

Abstract

We initiate the study of absorbing representations of CC^\ast-algebras with respect to closed operator convex cones. We completely determine when such absorbing representations exist, which leads to the question of characterising when a representation is absorbing, as in the classical Weyl-von Neumann type theorem of Voiculescu. In the classical case, this was proven by Elliott and Kucerovsky who proved that a representation is nuclearly absorbing if and only if it induces a purely large extension. By considering a related problem for extensions of CC^\ast-algebras, which we call the purely large problem, we ask when a purely largeness condition similar to the one defined by Elliott and Kucerovsky, implies absorption with respect to some given closed operator convex cone. We solve this question for a special type of closed operator convex cone induced by actions of finite topological spaces on CC^\ast-algebras. As an application of this result, we give KK-theoretic classification for certain CC^\ast-algebras containing a purely infinite, two-sided, closed ideal for which the quotient is an AF algebra. This generalises a similar result by the second author, S. Eilers and G. Restorff in which all extensions had to be full.

Keywords

Cite

@article{arxiv.1503.07799,
  title  = {Absorbing representations with respect to closed operator convex cones},
  author = {James Gabe and Efren Ruiz},
  journal= {arXiv preprint arXiv:1503.07799},
  year   = {2015}
}

Comments

71 pages. V2: minor general changes, changed definition of X-C*-algebras

R2 v1 2026-06-22T09:03:02.688Z