2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/77565Several relations on graphs, including primitive equivalence, explosion equivalence and strong shift equivalence, are examined and shown to preserve either the graph groupoid, a construction of Kumjian, Pask, Raeburn, and Renault, or the groupoid of a pointed version of the graph. Thus these relations preserve either the isomorphism class or the Morita equivalence class of the graph C*-algebra, as defined by Kumjian, Pask, and Raeburn.16 pages, AMSLaTeX, XY-pic, minor changes (including new definition of primitive transfer to avoid pathological cases)Operator Algebrastext