Can anyone help me understand what's going on in the last example of the main "Acquisition" document, <http://www.digicool.com/releases/ExtensionClass/Acquisition.html>? I think I understand how the various "complex expressions" relate to the equivalent expression in terms of the '__of__' operator, except for the very last case, "a.b.c.x". I just can't follow why the equivalent expression isn't x.__of__(a).__of__(c.__of__(b.__of__(a))) rather than the more complex answer given: x.__of__(a).__of__(b.__of__(a)).__of__(c.__of__(b.__of__(a))) When I run the test cases given in the document I see that the latter does match the behavior, but I find that baffling. In particular, why is the effective search order x-a-b-c rather than x-a-c-b? It almost looks like the effective search order could be described as "up through the containment heirarchy, then down through the remaining acquired path", but I'm not at all sure if that's a valid generalization. Can anyone shed some light on this for me? -- Fred Yankowski fred@OntoSys.com tel: +1.630.879.1312 Principal Consultant www.OntoSys.com fax: +1.630.879.1370 OntoSys, Inc 38W242 Deerpath Rd, Batavia, IL 60510, USA