Context-free grammars, differential operators and formal power series
نویسندگان
چکیده
منابع مشابه
Differential Operators and the Wheels Power Series
An earlier work of the author’s showed that it was possible to adapt the Alekseev-Meinrenken Chern-Weil proof of the Duflo isomorphism to obtain a completely combinatorial proof of the Wheeling isomorphism. That work depended on a certain combinatorial identity, which said that a certain composition of elementary combinatorial operations arising from the proof was precisely the Wheeling operati...
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The topic of this paper is formal solutions of linear dierential equations with formal power series coeecients. The method proposed for computing these solutions is based on factorization of diierential operators. The notion of exponential parts is introduced to give a description of factorization properties and to characterize the formal solutions. The algorithms will be described and their im...
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The question arises from time to time what the relation is between dependency grammars (DG’s) and phrase-structure grammars. A classic paper by Gaifman [1] would appear to have laid the issue to rest, by proving that dependency grammars are a special case of context-free grammars (CFG’s). Gaifman proves that dependency grammars are equivalent to a proper subset of phrasestructure grammars, thos...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 1993
ISSN: 0304-3975
DOI: 10.1016/0304-3975(93)90307-f