... paper,we analyze the following three model families:In the HMM, the input x is a sequence of wordsand the output y is the corresponding sequence of part -of- speech tags.In the PCFG, the input x ... summarize the predictions of the supervised system. If thesematch the empirical counts, then the M-step does notchange the parameters. But if the supervised systempredicts too many JJs, for example, ... on the distance from the true θ∗ for the HMM as we increase the number of examples.In the unsupervised case, we use the followingprocedure to obtain a surrogate for ˆθ: initialize EMwith the...