In ACE, nominal predicates corefer with their subject (2), and appositive phrases corefer with the noun they are modifying (3).
they do not fall under the identity relation in OntoNotes, which follows the linguistic understanding of coreference according to which nominal predicates and appositives express properties of an entity rather than refer to a second (coreferent) entity (van Deemter and Kibble, 2000).