The singular unit can thus use these gates to reliably store number information across long-range dependencies.
the unit can (enumeration follows the same order as the panels in Figure 1c): (1) encode subject number viaC t subject with different values for singular and plural; (2) open the input gate only when a singular subject is presented (i t subject = 1 in light-blue curves only) and protect it from interfering nouns (i t = 0, t subject < t < t verb ); (3) at the same time, clear the cell from previously stored information (f t subject = 0) and then store subject number across the entire dependency (f t = 1, t subject < t < t verb ); (4) this will result in stable encoding of subject number in the cell C t throughout the dependency; (5) finally, output subject number at the right moment, when predicting the verb form (o t verb −1 = 1) (Eq.