منابع مشابه
Sequentially Indexed Grammars
This paper defines the grammar class of sequentially indexed grammars. Sequentially indexed grammars are the result of a change in the index stack handling mechanism of indexed grammars [Aho68, Aho69]. Sequentially indexed grammars are different from linear indexed grammars [Gaz88]. Like indexed languages, sequentially indexed languages are a fully abstract language class. Unlike indexed langua...
متن کاملExtending Linear Indexed Grammars
This paper presents a possibility to extend the formalism of linear indexed grammars. The extension is based on the use of tuples of pushdowns instead of one pushdown to store indices during a derivation. If a restriction on the accessibility of the pushdowns is used, it can be shown that the resulting formalisms give rise to a hierarchy of languages that is equivalent with a hierarchy defined ...
متن کاملIndexed Languages and Unification Grammars
T h e occu rren ce o f purely syn tactica l cross-serial depen den cies in S w iss-G erm an show s that con text-free gram m ars can n ot describe the string sets o f natu ral lan guage [Shi85]. T h e least class in the C h om sk y hierarchy th at can d escribe u n lim ited cross-serial depen dencies is in dexed g ram m ars [A h o 68]. G azd a r discuss in [G a z88] the ap p licab ility o f in...
متن کاملFrom indexed grammars to generating functions
We extend the DSV method of computing the growth series of an unambiguous context-free language to the larger class of indexed languages. We illustrate the technique with numerous examples.
متن کاملA Tractable Extension of Linear Indexed Grammars
Vijay-Shanker and Weir (1993) show that Linear Indexed Grammars (LIG) can be processed in polynomial time by exploiting constraints which make possible the extensive use of structure-sharing. This paper describes a formalism that is more powerful than LIG, but which can also be processed in polynomial time using similar techniques. The formalism, which we refer to as Partially Linear PATR (PLPA...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 1986
ISSN: 0304-3975
DOI: 10.1016/0304-3975(86)90147-7