5. The system of claim 1 , further comprising: an augmentation module configured to, for at least one node in the first proposition tree, associate, with the at least one node, a word having a relationship to the at least one node to form a first augmented proposition tree.
5. The system of claim 1 , further comprising: an augmentation module configured to, for at least one node in the first proposition tree, associate, with the at least one node, a word having a relationship to the at least one node to form a first augmented proposition tree. 6. The system of claim 5 , wherein the relationship is a co-reference relationship.