Reference Resolution
The Jet reference resolver resolves anaphoric references to noun phrases.
It is intended to be invoked as the last step in processing each sentence
in a document.
The input to reference resolution consists of a set of annotations of
type constit with type=ngroup. These are called the
'mentions'. Each such annotation should have a pa feature
giving its predicate-argument structure, and -- if its head is a name --
the feature isName with some non-null value.
The output of reference resolution is a set of annotations of type entity.
Each entity annotation corresponds to a set of one or more mentions
which are deemed to be coreferential. The entity annotation
has the features head, position, mentions, number,
name,
and human.
Mentions are resolved as follows:
-
a common noun mention is resolved with the closest prior mention with the
same head, or with a head which is associated with the same concept or
a more specific concept in the concept hierarchy
-
a name mention is resolved with the closest prior mention with the same
name, or a superstring of the current name (so that, for example, "Bush"
will be resolved with "George Bush")
-
a third-person pronoun mention ("he", "she", "it", "they", "him", "her",
"them") will be resolved with the closest prior mention which agrees with
the pronoun in number and human-ness (antecedents of "he", "she", "him",
and "her" must be human; antecedents of "it" must not be human).
Human-ness for nouns is based on the human feature in the predicate-argument
structure; for names, person names are considered human, while
other names are considered non-human. This classification is slightly
incorrect since the dictionary labels an entry as human if any sense (not
necessarily the most common sense) of that entry is human.
-
a first- or second- person pronoun is resolved with the closest prior mention
of the same pronoun
If no prior mention satisfies the given constraints, a new entity is created.
In addition, after mentions are resolved, reference resolution searches
for annotations of type event. For each event, it generates
an annotation of type r-event which is identical except that any
feature whose value is a mention (ngroup) is replaced by the entity
to which the mention was resolved.