XDI graph model node type diagram

Another project on my trip was to draw the diagram illustrating the taxonomy of node types in the XDI graph model that I plan to include in the XDI Core 1.0 spec. The outcome is below. Notes:

This reflects all the same types as on https://wiki.oasis-open.org/xdi/GraphModelStructure except the classification is slightly different.

The only interesting new placement is Variable. Before I had just classified it as a different type of context. But a variable syntax (curly brackets) has more in common with graph syntax (parentheses) than anything else. And a variable can include an entire graph. So it seems to make sense to include it in the graph tree.

Thoughts before I move forward with publishing this?

=Drummond