Abstract
The paper introduces Treex CR, a coreference resolution (CR) system not only for Czech. As its name suggests, it has been implemented as an integral part of the Treex NLP framework.
The main feature that distinguishes it from other CR systems is that it operates on the tectogrammatical layer, a representation of deep syntax. This feature allows for natural handling of elided expressions, e.g. unexpressed subjects in Czech as well as generally ignored English anaphoric expression - relative pronouns and zeros.
The system implements a sequence of mention ranking models specialized at particular types of coreferential expressions (relative, reflexive, personal pronouns etc.). It takes advantage of rich feature set extracted from the data linguistically preprocessed with Treex.
We evaluated Treex CR on Czech and English datasets and compared it with other systems as well as with modules used in Treex so far.