This is not an issue of concern to (Teufel and Moens, 2002), but relates to the notion of NUCLEUS and SATELLITE clauses, which form the foundation of Rhetorical Structure Theory (Mann and Thompson, 1998), and guides the summarisation paradigm of (Marcu, 1998a;Marcu, 1998b).
the difference here is that we define a-priori certain categories to be independent (have the property of playing the role of nucleus in the discourse) and specify their relation with particular types of dependent categories.