polyhierarchy

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Polyhierarchy
This page http://tagunity.wikispaces.com/polyhierarchy DRAFT 1161149276

//todo define polyhierarchy//

e.g. defined "permitting some terms to be listed in multiple categories" of a taxonomy, or branches of a hierarchy (Rosenfeld & Morville 2002, p. 203 check). Polyhierarchical classification follows the biologist’s observation of the natural world of situations where and organism the natural world exhibits "characteristics of multiple categories," (Rosenfeld & Morville 2002, p. 203). In Rosenfeld and Morville view, "polyhierarchy is unavoidable in large info systems" (2002, p. 203), since in compound terms are more common large systems. For example [example compound terms from Morville, 2005]

As Peter Morville explains, some categories or classificaitons may be sub-categories of multiple hierarchies.
 * Example of polyhierarchy in medicine**

Consider for example, that viral pneumonia is both a **viral** disease and a **respitory** tract disease; both viral disease and a respitory tract disease sub-classifications of the **disease hierarchy**, and viral pneumonia is a sub-category of both, (Morville, 2005 p. 128; & see platypus paradox).