Focusing mostly on Feature-Based Lexicalized Tree-Adjoining Grammars (FB-LTAG) (but using Interaction Grammars [IG] and Multi-Component Tree-Adjoining Grammars [MC-TAG] to illustrate flexibility), we argue that XMG departs from other existing computational frameworks for designing tree-based grammars in three main ways: r First, XMG is a declarative language.
grammaticality is defined in an order-independent fashion by a set of well-formedness constraints rather than by procedures.