Unni Cathrine Eiken February 2005

This thesis explores the value of using co-occurrence patterns to create concept groups that can
act as an aid in the process of finding what a pronoun refers to. In order to find the entity that the
pronoun han (he) refers to in example (1-1), the following two alternative patterns can be
considered:
(1- 3)
a. lensmann etterlyser vitne sergeant calls-for witness
b. gjerningsmann etterlyser vitne perpetrator calls-for witness
When considering which of these patterns is the most likely one, data collected from a corpus
can be consulted (Dagan and Itai 1990; Dagan et al. 1995; Nasukawa 1994; inter al.). If one of
the patterns is found literally in the corpus, it will receive a strong preference. If none of the
patterns occur in the data collection, similar patterns can be considered. Given that the patterns
in example (1-4) below do feature in the data collection, they can contribute to guessing the
correct referent for the anaphor in example (1-1):
(1- 4)
a. politi etterlyser vitne police call-for witness
b. etterforsker etterlyser vitne investigator calls-for witness
c. lensmann avhører vitne sergeant interviews witness
d. politi avhører person police interview person
e. gjerningsmann dreper offer perpetrator kills victim
f. gjerningsmann angriper kvinne perpetrator attacks woman
In view of the patterns in (1-4), the word lensmann (sergeant) engages in contexts similar to
those of politi (police), which in turn occurs in similar contexts to etterforsker (investigator). By
using association techniques, lensmann can be associated with the other arguments which occur
in similar linguistic environments, and subsequently be preferred as the referent in (1-1).
Approaches within the field of anaphora resolution have in recent years focused on knowledge-
poor strategies used in combination with corpora, at the same time, the notion of constructing a
large and comprehensive base of real-world knowledge has been abandoned somewhat (see
Mitkov 2003 for a brief overview). The approach in the present work expands the co-occurrence
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