A rule can potentially apply to a base form in a number of places; we define an anchored rule A = (R, i, j, b) to be the application of R to a span (i, j) in b.
a is only a valid anchoring if the substring of b between i and j matches the input of rule R. Given a set a of non-overlapping anchored rules for b, each entry of T (b) can be deterministically produced by rewriting each anchored rule's span (i, j) using the rule R. the task of predicting T (b) is equivalent to selecting a coherent subset a of anchored rules from the set of all possible anchored rules for this base form.