New York Journal of Mathematics
Volume 7 (2001) 233-256


Mark Tomforde

Ext Classes and Embeddings for C*-Algebras of Graphs with Sinks

Published: November 10, 2001
Keywords: Cuntz-Krieger algebra, graph algebra, 1-sink extension, CK-equivalence, C*-algebra
Subject: 19K33 and 46L55

We consider directed graphs E 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 such graphs are equal in Ext(C*(G)) if and only if the associated C*-algebra of one can be embedded as a full corner in the C*-algebra of the other in a particular way. If every loop in G has an exit, then we are able to use this result to generalize some known classification theorems for C*-algebras of graphs with sinks.

Author information

Department of Mathematics, Dartmouth College, Hanover, NH 03755-3551, USA