Hierarchies within range space
From LMNL to OHCO
LMNL provides a markup syntax for annotating arbitrary ranges, irrespective of hierarchical relations, in text. A LMNL processor can parse this syntax (or any other syntax, if mapped) into a generalized data model, which can be queried and processed. Among the applications that LMNL supports readily is the creation of visual "sketches" of the markup on a document, e.g. using SVG. Such sketches can discover and depict any range relations of interest. It turns out the overlap is often less interesting than the hierarchies.
Examining texts showing overlapping hierarchies (MCH or multiple concurrent hierarchies) suggests some interesting things about the evolution, purposes and uses of the OHCO (ordered hierarchy of content objects) as a concept applied to "documents" or literary artifacts in general— and by implication of any hierarchical data model such as XML.