CONDITION (K) FOR BOOLEAN DYNAMICAL SYSTEMS

We generalize Condition (K) from directed graphs to Boolean dynamical systems and show that a locally finite Boolean dynamical system $({{\mathcal {B}}},{{\mathcal {L}}},\theta )$ with countable ${{\mathcal {B}}}$ and ${{\mathcal {L}}}$ satisfies Condition (K) if and only if every ideal of its $C^*$ -algebra is gauge-invariant, if and only if its $C^*$ -algebra has the (weak) ideal property, and if and only if its $C^*$ -algebra has topological dimension zero. As a corollary we prove that if the $C^*$ -algebra of a locally finite Boolean dynamical system with ${{\mathcal {B}}}$ and ${{\mathcal {L}}}$ countable either has real rank zero or is purely infinite, then $({{\mathcal {B}}}, {{\mathcal {L}}}, \theta )$ satisfies Condition (K). We also generalize the notion of maximal tails from directed graph to Boolean dynamical systems and use this to give a complete description of the primitive ideal space of the $C^*$ -algebra of a locally finite Boolean dynamical system that satisfies Condition (K) and has countable ${{\mathcal {B}}}$ and ${{\mathcal {L}}}$ .

The classification of certain ASH C*-algebras of real rank zero

In this paper, using ordered total K-theory, we give a K-theoretic classification for the real rank zero inductive limits of direct sums of generalized dimension drop interval algebras.

A decomposition theorem for real rank zero inductive limits of 1-dimensional non-commutative CW complexes

In this paper, we consider the real rank zero [Formula: see text]-algebras which can be written as an inductive limit of the Elliott–Thomsen building blocks and prove a decomposition result for the connecting homomorphisms; this technique will be used in the classification theorem.

Closed Convex Hulls of Unitary Orbits in Certain Simple Real Rank Zero C* -algebras

In this paper, we characterize the closures of convex hulls of unitary orbits of self-adjoint operators in unital, separable, simple C* -algebras with non-trivial tracial simplex, real rank zero, stable rank one, and strict comparison of projections with respect to tracial states. In addition, an upper bound for the number of unitary conjugates in a convex combination needed to approximate a self-adjoint are obtained.

Strict Comparison of Positive Elements in Multiplier Algebras

Main result: If a C*-algebrais simple,σ-unital, hasfinitely many extremal traces, and has strict comparison of positive elements by traces, then its multiplier algebraalso has strict comparison of positive elements by traces. The same results holds if finitely many extremal traces is replaced byquasicontinuous scale. A key ingredient in the proof is that every positive element in the multiplier algebra of an arbitrary σ-unital C* -algebra can be approximated by a bi-diagonal series. As an application of strict comparison, ifis a simple separable stable C* -algebra with real rank zero, stable rank one, and strict comparison of positive elements by traces, then whether a positive element is a positive linear combination of projections is determined by the trace values of its range projection.

Maps preserving Jordan triple product on the self-adjoint elements of C∗-algebras

Let [Formula: see text] and [Formula: see text] be two unital [Formula: see text]-algebras with unit [Formula: see text]. It is shown that the mapping [Formula: see text] which preserves arithmetic mean and Jordan triple product is a difference of two Jordan homomorphisms provided that [Formula: see text]. The structure of [Formula: see text] is more refined when [Formula: see text] or [Formula: see text]. Furthermore, if [Formula: see text] is a [Formula: see text]-algebra of real rank zero and [Formula: see text] is additive and preserves absolute value of product, then [Formula: see text] such that [Formula: see text] (respectively, [Formula: see text]) is a complex linear (respectively, antilinear) ∗-homomorphism.

On Extensions of Stably FiniteC*-Algebras (II)

For any C*-algebra A with an approximate unit of projections, there is a smallest ideal I of A such that the quotient A/I is stably finite. In this paper a sufficient and necessary condition for an ideal of a C*-algebra with real rank zero to be this smallest ideal is obtained by using K-theory