  Electre Tri is a set of methods designed to sort alternatives evaluated on
several criteria into ordered categories. In these methods, alternatives are
assigned to categories by comparing them with reference profiles that represent
either the boundary or central elements of the category. The original Electre
Tri-B method uses one limiting profile for separating a category from the
category below. A more recent method, Electre Tri-nB, allows one to use several
limiting profiles for the same purpose. We investigate the properties of
Electre Tri-nB using a conjoint measurement framework. When the number of
limiting profiles used to define each category is not restricted, Electre
Tri-nB is easy to characterize axiomatically and is found to be equivalent to
several other methods proposed in the literature. We extend this result in
various directions.
