tailieunhanh - Báo cáo khoa học: "Identifying Topic and Focus by an Automatic Procedure"

An algorithm for automatic identification of topic and focus of the sentence is presented, based on dependency syntax and using written input, which is much more ambiguous than spoken utterance. | Identifying Topic and Focus by an Automatic Procedure Eva Hạjièová Petr Sgall Institute of Formal and Applied Linguistics Charles University Malostranské nám. 25 118 00 Praha 1 Czech Republic hajicova@cspgukl 1 .bitnet sgall@cspgukl 1 .bitnet Hana Skoumalová Institute of Theoretical and Computational Linguistics Charles University Celetná 13 110 00 Praha 1 Czech Republic skoumal@prahal . Abstract An algorithm for automatic identification of topic and focus of the sentence is presented based on dependency syntax and using written input which is much more ambiguous than spoken utterance. 1. The dichotomy of topic and focus based in the Praguean Functional Generative Description on the scale of communicative dynamism underlying word order is relevant not only for a possible placement of the sentence in a context but also for its semantic interpretation. The underlying word order differs from the surface one especially in that the verb stands more to the right than all its complementations belonging to the topic of the sentence or to the local topic of the clause headed by the verb and more to the left than those belonging to the focus. Using a dependency grammar or more or less equivalently a flat structure in a constituency based grammar we can illustrate this by the following example where 1 is a simplified underlying representation of 1 on a reading answering . the question Where has Charles found my pen 1 Charles has found your pen in a box lying on the table. 1 Charles you Appurt pen obj Rel Actlie table IjOCOO Loc In 1 every pair of parentheses encompasses a dependent item . coưesponds to an edge of the linearized dependency tree the indices of parentheses denote kinds of dependency valency slots or theta roles and adjuncts Act stands for Actor underlying Subject Appurt for Appurtenance Possessivity in a broader sense Obj for Objective underlying Object Loc for Locative Gener for the General Relationship of an adjunct to its .