Once the EDUs are identified, the discourse parsing problem is determining which discourse units (EDUs or larger units) to relate (i.e., the structure), and what relations (i.e., the labels) to use in the process of building the DT.
discourse parsing requires: (1) a parsing model to explore the search space of possible structures and labels for their nodes, and (2) a parsing algorithm for selecting the best parse tree(s) among the candidates.