Resolving Ambiguities of Chinese Conjunctive Structures by Divide-and-conquer Approaches

This paper presents a method to enhance a Chinese parser in parsing conjunctive structures. Long conjunctive structures cause long-distance dependencies and tremendous syntactic ambiguities. Pure syntactic approaches hardly can determine boundaries of conjunctive phrases properly. In this paper, we propose a divide-andconquer approach which overcomes the difficulty of data-sparseness of the training data and uses both syntactic symmetry and semantic reasonableness to evaluate ambiguous conjunctive structures. In comparing with the performances of the PCFG parser without using the divide-andconquer approach, the precision of the conjunctive boundary detection is improved from 53.47% to 83.17%, and the bracketing f-score of sentences with conjunctive structures is raised up about 11 %.