UCM-I: A Rule-based Syntactic Approach for Resolving the Scope of Negation

This paper presents one of the two contributions from the Universidad Complutense de Madrid to the *SEM Shared Task 2012 on Resolving the Scope and Focus of Negation. We describe a rule-based system for detecting the presence of negations and delimitating their scope. It was initially intended for processing negation in opinionated texts, and has been adapted to fit the task requirements. It first detects negation cues using a list of explicit negation markers (such as not or nothing), and infers other implicit negations (such as affixal negations, e.g, undeniable or improper) by using semantic information from WordNet concepts and relations. It next uses the information from the syntax tree of the sentence in which the negation arises to get a first approximation to the negation scope, which is later refined using a set of post-processing rules that bound or expand such scope.