Published online by Cambridge University Press: 20 November 2018
The Cuntz-Krieger algebra ${{\mathcal{O}}_{B}}$ is defined for an arbitrary, possibly infinite and infinite valued, matrix
$B$ . A graph
${{C}^{*}}$ -algebra
${{G}^{*}}\left( E \right)$ is introduced for an arbitrary directed graph
$E$ , and is shown to coincide with a previously defined graph algebra
${{C}^{*}}\left( E \right)$ if each source of
$E$ emits only finitely many edges. Each graph algebra
${{G}^{*}}\left( E \right)$ is isomorphic to the Cuntz-Krieger algebra
${{\mathcal{O}}_{B}}$ where
$B$ is the vertex matrix of
$E$ .