Recent work on Semantic Role Labeling (SRL) has shown that syntactic information is critical to detect and extract predicate argument structures. As syntax is expressed by means of structured data, i.e. parse trees, its encoding in learning algorithms is rather complex. In this paper, we apply tree kernels to encode the whole predicate argument structure in Support Vector Machines (SVMs). We extract from the sentence syntactic parse the subtrees that span potential argument structures of the target predicate and classify them in incorrect or correct structures by means of tree kernel based SVMs. Experiments on the PropBank collection show that the classification accuracy of correct/incorrect structures is remarkably high and helps to improve the accuracy of the SRL task. This is a piece of evidence that tree kernels provide a powerful mechanism to learn the complex relation between syntax and semantics.
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