LEARNING THE STRUCTURE OF HIERARCHICAL EXTRACTION MODELS

A hierarchical extraction model for a label hierarchy may be implemented by a weighted hierarchical state machine whose structure and/or weights are determined in part from a statistical distribution of label sequences as determined from training data. In accordance with various embodiments, the hierarchical state machine includes one or more non-cyclic directed chains of states representing at least a subset of the label sequences, and transitions weighted based at least in part on the statistical distribution.