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We geometrically describe the relation induced on a set of graphs by isomorphism of their associated graph C*-algebras as the smallest equivalence relation generated by five types of moves. The graphs studied have finitely many vertices and finitely or countably infinitely many edges, corresponding to unital and separable C*-algebras. [ABSTRACT FROM AUTHOR]

Since their inception in the 1930s by von Neumann, operator algebras have been used to shed light on many mathematical theories. Classification results for self-adjoint and non-self-adjoint operator algebras manifest this approach, but a clear connection between the two has been sought since their emergence in the late 1960s. We connect these seemingly separate types of results by uncovering a hierarchy of classification for non-self-adjoint operator algebras and $C^{*}$ -algebras with additional $C^{*}$ -algebraic structure. Our approach naturally applies to algebras arising from $C^{*}$ -correspondences to resolve self-adjoint and non-self-adjoint isomorphism problems in the literature. We apply our strategy to completely elucidate this newly found hierarchy for operator algebras arising from directed graphs. [ABSTRACT FROM AUTHOR]

There are many classes of nonsimple graph C*-algebras that are classified by the six-term exact sequence in K-theory. In this paper we consider the range of this invariant and determine which cyclic six-term exact sequences can be obtained by various classes of graph C*-algebras. To accomplish this, we establish a general method that allows us to form a graph with a given sixterm exact sequence of K-groups by splicing together smaller graphs whose C*- algebras realize portions of the six-term exact sequence. As rather immediate consequences, we obtain the first permanence results for extensions of graph C*-algebras. We are hopeful that the results and methods presented here will also prove useful in more general cases, such as situations where the C*-algebras under investigation have more than one ideal and where there are currently no relevant classification theories available. [ABSTRACT FROM AUTHOR]

As recently pointed out by Gabe, a fundamental paper by Elliott and Kucerovsky concerning the absorption theory for C ⁎ -algebras contains an error, and as a consequence we must report that Lemma 4.5 in [3] is not true as stated. In this corrigendum, we prove an adjusted statement and explain why the error has no consequences to the main results of [3] . In particular, it is noted that all the authors' claims concerning Morita equivalence or stable isomorphism of graph C ⁎ -algebras remain correct as stated. [ABSTRACT FROM AUTHOR]

Abstract: We give a classification result for a certain class of -algebras over a finite topological space X in which there exists an open set U of X such that U separates the finite and infinite subquotients of . We apply our results to -algebras arising from graphs. [Copyright &y& Elsevier]

At the cost of restricting the nature of the involved K-groups, we prove a classification result for a hitherto unexplored class of graph C*-algebras, allowing us to classify all graph C*-algebras on finitely many vertices with a finite linear ideal lattice if all pair of vertices are connected by infinitely many edges when they are connected at all. [ABSTRACT FROM AUTHOR]

Abstract: For a certain class of extensions of -algebras in which B and A belong to classifiable classes of -algebras, we show that the functor which sends to its associated six term exact sequence in K-theory and the positive cones of and is a classification functor. We give two independent applications addressing the classification of a class of -algebras arising from substitutional shift spaces on one hand and of graph algebras on the other. The former application leads to the answer of a question of Carlsen and the first named author concerning the completeness of stabilized Matsumoto algebras as an invariant of flow equivalence. The latter leads to the first classification result for nonsimple graph -algebras. [Copyright &y& Elsevier]

We employ results from KK-theory, along with quasidiagonality techniques, to obtain wide-ranging classification results for nuclear C*-algebras. Using a new realization of the Cuntz picture of the Kasparov groups we show that two morphisms inducing equal KK-elements are approximately stably unitarily equivalent. Using K-theory with coefficients to associate a partial KK-element to an approximate morphism, our result is generalized to cover such maps. Conversely, we study the problem of lifting a (positive) partial KK-element to an approximate morphism. These results are employed to obtain classification results for certain classes of quasidiagonal C*-algebras introduced by H. Lin, and to reprove the classification of purely infinite simple nuclear C*-algebras of Kirchberg and Phillips. It is our hope that this work can be the starting point of a unified approach to the classification of nuclear C*-algebras. [ABSTRACT FROM PUBLISHER]