ITRI-00-01
Richard Power

Mapping Rhetorical Structures to Text Structures
by Constraint Satisfaction

A method is described by which a rhetorical-structure
tree can be realized by a text structure made up of
sections, paragraphs, sentences, and other
textual patterns, with discourse connectives added (in
the correct positions) to mark rhetorical relations.
We show that text-structuring can be formulated
as a Constraint Satisfaction Problem, so that all solutions
respecting constraints on text-structure formation and
structural compatibility can be efficiently generated.
Two models are described: the first simplifies by
excluding intended structures such as vertical lists;
the second allows them.
Of the many solutions generated by this method, some are
stylistically preferable to others; we show how further
constraints can be applied in order to select the best
versions.