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Guillem Gascó, Joan-Andreu Sánchez. A* Parsing with Large Vocabularies. Proceedings of the International Conference Recent Advances in Natural Language Processing, 2007. pp. 215-219.

In this work, we study an A∗ parsing algorithm to obtain exact Viterbi parse selection for a real task with a large vocabulary. We propose two different new bounds for parsing. The rst one includes lexical information and guarantees the optimal solution with an important cost reduction. The second one offers a larger cost reduction but the optimality of the solution is not guaranteed. Nevertheless, in practice the optimal solution for this second bound is lost in very few cases. Experiments on the Penn Treebank corpus are reported in order to show the improvements obtained with the proposed bounds.