The Rhetorical Structure Theory (RST) Discourse Treebank consists of 385 Wall Street Journal articles from the Penn Treebank annotated with discourse structure in the RST framework along with human-generated extracts and abstracts associated with the source documents.
In the RST framework (Mann and Thompson, 1988), a text's discourse structure can be represented as a tree in four aspects:
(1) the leaves correspond to text fragments called elementary discourse units (the mininal discourse units); (2) the internal nodes of the tree correspond to contiguous text spans; (3) each node is characterized by its nuclearity, or essential unit of information; and (4) each node is also characterized by a rhetorical relation between two or more non-overlapping, adjacent text spans.
The data in this release is divided into a training set (347 documents) and a test set (38 documents). All annotations were produced using a discourse annotation tool that can be downloaded from http://www.isi.edu/~marcu/discourse.