... between the whole TREE and the whole STRING (tri- vial), between the subtree 4(5(6),7) and the two occurrences of the substring "dog catcher" (non- trivial), etc. We shall do the ... in the form of a labeled tree, and the relation between a string of terms and a structural representation is defined as a mapping between elements of the set of substrings of the string and ... is the design of the multilevel structures, while the grammar formalism is the tool (notation) for expressing these multilevel structures, their related sentences, and the nature of the correspon-...