Here's a summary of what I think the changes to the JSDL schema should be, based on my understanding of what Igor proposed: Firstly, a little house-keeping: 'id' attributes should probably change name to 'profileGroup'; in the XML community, 'id' means something very specific (unique within a document) and our 'id' attribs are definitely not that. Now, to the substance. Firstly, an explanation. None of this is necessary for the primary goal of JSDL (providing a description of simple jobs); it only really becomes necessary when you embed JSDL within a wider context of, say, a large workflow. But this is a case that we will certainly want to support going forward. The gist of Igor's proposal is that we make JSDL somewhat more document-oriented, in a way similar to an XML Schema or a WSDL doc. To do this: Want to be able to declare things that can be referenced from elsewhere, together with having infrastructure that can do this referencing. -> Need a name attribute on many elements (I suspect this is not needed on Profile, but instead on Resource, etc.) of type NCname -> Need a ref attribute on all elements with a name attribute -> Allow named elements as direct children of topmost element (I forget the name; Job<SomethingOrOther>). These declarations have no meaning in themselves; they just exist to be referred to. -> New element to import declarations from some other document into a namespace, rather like <wsdl:import> (toplevel only). -> Non-toplevel elements may have ref attributes and no other content; name (a qualified name, not an NCname) must point to some element in the current document (or imported) with a suitable name element. -> Topmost element to have a targetNamespace attribute (I think that's it?) I'll write tomorrow on the the Application subtyping scheme. That's distinct from this proposal. Donal.