Coreference
In linguistics, coreference, sometimes written co-reference, occurs when two or more expressions refer to the same person or thing; they have the same referent. For example, in Bill said Alice would arrive soon, and she did, the words Alice and she refer to the same person. Co-reference is often non-trivial to determine. For example, in Bill said he would come, the word he may or may not refer to Bill. Determining which expressions are coreferences is an important part of analyzing or understanding the meaning, and often requires information from the context, real-world knowledge, such as tendencies of some names to be associated with particular species ("Rover"), kinds of artifacts ("Titanic"), grammatical genders, or other properties. Linguists commonly use indices to notate coreference, as in Billi said hei would come. Such expressions are said to be coindexed, indicating that they should be interpreted as coreferential. When expressions are coreferential, the first to occur is often a full or descriptive form (for example, an entire personal name, perhaps with a title and role), while later occurrences use shorter forms (for example, just a given name, surname, or pronoun). The earlier occurrence is known as the antecedent and the other is called a proform, anaphor, or reference. However, pronouns can sometimes refer forward, as in "When she arrived home, Alice went to sleep." In such cases, the coreference is called cataphoric rather than anaphoric. Coreference is important for binding phenomena in the field of syntax. The theory of binding explores the syntactic relationship that exists between coreferential expressions in sentences and texts. Types When exploring coreference, numerous distinctions can be made, e.g. anaphora, cataphora, split antecedents, coreferring noun phrases, etc. Several of these more specific phenomena are illustrated here: Anaphora a. The musici was so loud that iti couldn't be enjoyed. –The anaphor it follows the expression to which it refers (its antecedent). b. Our neighborsi dislike the music. If theyi are angry, the cops will show up soon. – The anaphor they follows the expression to which it refers (its antecedent). Cataphora a. If theyi are angry about the music, the neighborsi will call the cops. – The cataphor they precedes the expression to which it refers (its postcedent). b. Despite heri difficulty, Wilmai came to understand the point. – The cataphor her precedes the expression to which it refers (its postcedent) Split antecedents a. Caroli told Bobi to attend the party. Theyi arrived together. – The anaphor they has a split antecedent, referring to both Carol and Bob. b. When Caroli helps Bobi and Bobi helps Caroli, theyi can accomplish any task. – The anaphor they has a split antecedent, referring to both Carol and Bob. Coreferring noun phrases a. The project leaderi is refusing to help. The jerki thinks only of himself. – Coreferring noun phrases, whereby the second noun phrase is a predication over the first. b. Some of our colleagues1 are going to be supportive. These kinds of people1 will earn our gratitude. – Coreferring noun phrases,