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What is coreference?

Learn about coreference in PDT 2.0 with links between nodes and two types of coreference—grammatical and textual. Explore various examples and special cases to better understand this linguistic concept.

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What is coreference?

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  1. Coreferencein the PDT 2.0Zdeněk ŽabokrtskýInstitute of Formal and Applied LinguisticsCharles University in Prague

  2. What is coreference? • multiple expressions in a sentence or document can refer to the same thing … … John … …. … …. … … …. .. .. … .. he … … .. …. … …. ….. ……. REFERENCE COREFERENCE

  3. Coreference in PDT • links between tectogrammatical nodes • technically: pointer from an anaphor t-node to its antecedent t-node • links can form chains

  4. Two types of coreference • according to Functional Generative Description, two types of coreference distinguished: • grammatical coreference • (partially) determined by grammar rules • textual coreference • determined only by text meaning

  5. Grammatical coreference (1) • relative pronouns • “The man, who…”, “The man, whose …” • typical local configuration: … noun modified by the relative clause main verb of the relative clause … … relative pronoun

  6. Grammatical coreference (2) • reflexive pronouns • in Czech, pronouns referring to clause subject have reflexive form • typical local configuration: … main verb in the clause clause subject … … reflexive pronoun

  7. Grammatical coreference (3) • reconstructed (surface-unexpressed) actor of infinitive verbs • “He started to sing.” “They asked him to come.” • typical local configuration: … control verb … infinitive verb … #Cor.ACT - reconstructed coreferential actor

  8. Textual coreference • anaphors: • personal pronouns • possessive pronouns • reconstructed pronouns (pro-drop)

  9. Special cases • multiple antecedent: • two or more parallel links from a plural anaphor (Peter and Paul … they…) • cataphora • left-to-right links • segm – vague reference to the previous context • exoph - exophora

  10. Amount of data • manually annotated coreference in 50,000 sentences • around 45,000 coreference links

  11. Summary • coreference in PDT 2.0 • one of the largest coreference resources • two types of coreference links • grammatical coreference • textual coreference • anaphors: • pronouns (personal, possessive, relative, reflexive) • reconstructed nodes (pro-drops,actants of infinitive verbs,…)

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