Effect of Semantic Parsing Depth on the Identification of Paraphrases in Russian Texts

As a tool to solve the problem of identification of paraphrases in Russian texts, the paper proposes the semantic-syntactic parser SemSin and a semantic classifier. Several alternative methods for evaluating the similarity of sentence pairs-by words, by lemmas, by classes, by semantically related concepts, by predicate groups-have been analyzed. Advantages and drawbacks of the methods are discussed. The paraphrase identification quality has been shown to rise with increasing depth of using the semantic information. Yet, complementing the analysis with predicate groups, identified by the dependency tree, may even cause the identification to degrade due to the growing number of false positive decisions.