Relational Phrase Structure Grammar Applied to Mohawk Constructions
Irena Bellert · Kybernetika · 1966
Recently much concern has been given to the problem of the generative adequacy of different types of grammars, [ l ] , [2], [3], [4], [5], [6] and [7]. There are certain types of dependencies in languages which constitute a crucial test for grammars in this respect; languages with certain types of dependencies cannot be generated by certain grammars, while they can be generated by others. For instance, selfembedding properties constitute such a test, as it has been proven by Chomsky (see Theorem 33 in [4]) that self-embedding is a crucial property distinguishing finite state languages from phrase structure languages. Another property which is essential in distinguishing context-free from contextsensitive languages is that of unbounded cross dependencies. One of the languages possessing this property is, for instance, Chomsky's L3, which contains all sentences consisting of a string followed by that indentical string, and only these. ([5] p. 285). Chomsky has shown that there exists no context-free grammar for that language, and has presented a context-sensitive grammar for it ([4] p. 367, Theorem 15). However, Chomsky's context-sensitive rules for that grammar do not satisfy the condition that permutations be excluded in derivations, which condition has to be satisfied for a meaningful phrase structure representation of natural languages ([7] p. 144). The problem of cross dependencies has aroused linguistic interest by the evidence