In particular, for each category k ∈ K we assume a function score k which produces a positive score if the phrase is likely to belong to category k, and a negative score otherwise.
given this, the NE-Chunker is a function which searches a NE chunking for a sentence x according to the following optimality criterion: among the considered chunkings of the sentence, the optimal one is defined to be the one whose NE phrases maximize the summation of phrase scores.