Towards incremental semantic annotation

In this paper it is argued for the use of a type of notation that allows the incremental expression of semantic information. A sound incremental semantic annotation must be able to be extended without deleting any of the previous annotations in the same text. This way one can specify the semantic contents of textual information according to the resources and time available. To achieve this sort of incremental extensibility, the use of a flat notation is proposed by reifying all the predicates and operators in the (possibly nested) original expression. One such notation is introduced, and it is shown how the notation can express semantic information with the detail that matches our needs. Some interesting properties of this notation are also indicated. Finally, it is shown how this notation helps in the task of pin-point information retrieval by answer extraction, based on ExtrAns and WebExtrAns, two existing answer extraction systems.