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.
The theory of binding explores the syntactic relationship that exists between coreferential expressions in sentences and texts.
When exploring coreference, numerous distinctions can be made, e.g. anaphora, cataphora, split antecedents, coreferring noun phrases, etc.
[2] Several of these more specific phenomena are illustrated here: Semanticists and logicians sometimes draw a distinction between coreference and what is known as a bound variable.
That is, when two or more expressions are coindexed, it does not signal whether one is dealing with coreference or a bound variable (or as in the last example, whether it depends on interpretation).
To derive the correct interpretation of a text, or even to estimate the relative importance of various mentioned subjects, pronouns and other referring expressions must be connected to the right individuals.
Algorithms intended to resolve coreferences commonly look first for the nearest preceding individual that is compatible with the referring expression.
[5] Approaches to coreference resolution can broadly be separated into mention-pair, mention-ranking or entity-based algorithms.
The representation of a variable-width chain is more complex and computationally expensive than mention-based methods, which lead to these algorithms being mostly based on neural network architectures.