Relation nodes represent relations between facts. Although based on conceptual relations, they qualify as rhetorical in that only the subset of relations that could explicitly be conveyed is included in the text potential. Relations include e.g., Example, Concession, Amplification, Similarity, Contrast and ``In that''. Each relation has a nucleus and satellite (as in RST) as well as a set of precondition facts, which must be assimilated before the relation can be. There are no relations between relation-nodes in the text potential at present. Relation-nodes only link fact-nodes.
Relations in the text potential present a uniform interface as nodes connected to facts in the graph but are implemented by special-purpose procedures of varying complexity. Figure 2 shows a small sub-graph of the text-potential, showing two Concession relations between facts.
Figure 2: The Concession Relation