56 citations · 58 across the 3 of their papers we have counts for
6 papers · 2 filters
Simplicity of ultragraph algebras
Mark Tomforde
In this paper we analyze the structure of C*-algebras associated to ultragraphs, which are generalizations of directed graphs. We characterize the simple ultragraph algebras as wel…
A unified approach to Exel-Laca algebras and C*-algebras associated to graphs
Mark Tomforde
We define an ultragraph, which is a generalization of a directed graph, and describe how to associate a C*-algebra to it. We show that the class of ultragraph algebras contains the…
Computing K-theory and Ext for graph C*-algebras
D. Drinen, M. Tomforde
K-theory and Ext are computed for the C*-algebra C*(E) of any countable directed graph E. The results generalize the K-theory computations of Raeburn and Szymanski and the Ext comp…
Ext classes and embeddings for C*-algebras of graphs with sinks
Mark Tomforde
We consider directed graphs E which have been obtained by adding a sink to a fixed graph G. We associate an element of Ext(C*(G)) to each such E, and show that the classes of two s…
Computing Ext for graph algebras
Mark Tomforde
For a row-finite graph G with no sinks and in which every loop has an exit, we construct an isomorphism between Ext(C*(G)) and coker(A-I), where A is the vertex matrix of G. If c i…
Classification theorems for the C*-algebras of graphs with sinks
Iain Raeburn, Mark Tomforde, Dana P. Williams
We consider graphs E which have been obtained by adding one or more sinks to a fixed directed graph G. We classify the C*-algebra of E up to a very strong equivalence relation, whi…