SYNTAX: notion of
binding theory: alpha locally binds
beta iff alpha binds beta, and for all gamma, if gamma binds beta then either
gamma binds alpha or gamma is alpha. In other words: alpha locally binds beta iff
alpha is the closest binder of beta. Consequently, beta is locally A-bound if its
local binder occupies an A-position, and locally A-bar-bound if its closest binder
is in an A-bar position.