Disambiguation of coordinate Expressions in Japanese by Extracting Mutual Case Relation

Japanese coordinate noun phrases by the particle TO are often ambiguous on whether it means two parallel propositions (and), or a mutual case relation (with or against), as deep case structure. It was a hard problem to determine it, though they are widely used. We propose a method of solving the ambiguity by analyzing mutualness of verbs and adjectives. The mutualness is determined by three features of each verb or adjective. The first feature Indicates permission of mutual expression in the subject, and the second In the object. The last shows if a verb is voluntary. Using this method we design a parsing mechanism, where matching of features is represented as neutralization between predicate arguments.