... tor, &, unique to SFG. Formulas involving ~ are called e~tension formulas and they have a more complicated semantics. For example, Dative has the following informal interpretation: Two ... 2. For c = 1, ,k, for each Graph(hi) of Wc, add [ni, c - 1, c] to Se. B. Completions: For c = 1, , k, do repeatedly until no more states can be added to Se: 1. Leftward Completion: For ... state-set Si as state i:Q. For an input string w = Wl, ,w,~, initialization cre- ates n state-sets and for 1 < i < n, adds states i : Qj,1 _< j < k, to Si , one for each of the k S-graphs...