Notes on computational linguistics.pdf - UCLA Department of ...

Stabler - Lx 185/209 2003
(46) Does any construction similar to a n b n c n occur in any natural language? There are arguments that
English is not context free, but the best known arguments consider parts of English which are similar
to a i b j a i b j or the language
{xx| x any nonempty str ing of ter minal symbols}
These languages are not context-free. Purported examples of this kind of thing occur in phonological/morphological
reduplication, in simplistic treatments of the “respectively” construction in English;
in some constructions in a Swiss-German dialect. Some classic discussions of these issues are reprinted
in Savitch et al. (1987).
(47) Tree grammars and automata that accept trees have been studied extensively (Gecseg and Steinby, 1984),
particularly because they allow elegant logical (in fact, model-theoretic) characterizations (Cornell and
Rogers, 1999). Tree automata have also been used in the analysis of non-CFLs (Mönnich, 1997; Michaelis,
Mönnich, and Morawietz, 2000; Rogers, 2000).
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