Parts of the river valley often meander), while the set of singular verbs has, meanders, and is are assigned much lower probability mass since they are syntactically illicit.
as long as the RNNG makes the accurate structural generalisations (and we have shown that it largely does in §3), every training instance provides the student LSTM with a wealth of information about all the possible legitimate continuations according to the predictions of the hierarchical teacher, thereby making it easier for the student to learn the appropriate hierarchical constraints and generalisations.