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Showing papers on "Indexed language published in 1988"


Book ChapterDOI
01 Jan 1988
TL;DR: This chapter discusses the class of context-free phrase structure grammars, which has been alluded to a number of times in the recent linguistic literature: by Klein (1981) in connection with nested comparative constructions, by Dahl (1982) in connected with topicalised pronouns, by Engdahl ( 1982) and Gazdar (1982).
Abstract: If we take the class of context-free phrase structure grammars (CFPSGs) and modify it so that (i) grammars are allowed to make use of finite feature systems and (ii) rules are permitted to manipulate the features in arbitrary ways, then what we end up with is equivalent to what we started out with Suppose, however, that we take the class of contextfree phrase structure grammars and modify it so that (i) grammars are allowed to employ a single designated feature that takes stacks of items drawn from some finite set as its values, and (ii) rules are permitted to push items onto, pop items from, and copy the stack What we end up with now is no longer equivalent to the CF-PSGs but is significantly more powerful, namely the indexed grammars (Aho, 1968) This class of grammars has been alluded to a number of times in the recent linguistic literature: by Klein (1981) in connection with nested comparative constructions, by Dahl (1982) in connection with topicalised pronouns, by Engdahl (1982) and Gazdar (1982) in connection with Scandinavian unbounded dependencies, by Huybregts (1984) and Pulman and Ritchie (1984) in connection with Dutch, by Marsh and Partee (1984) in connection with variable binding, and doubtless elsewhere as well

185 citations


Journal ArticleDOI
TL;DR: Some relative decision problems concerning LR( k ), LL-regular, and LR-regular grammars and languages are shown to be undecidable and iteration theorems are derived which allow the proof that certain languages are no: LL- regular of LR- regular.

2 citations


Journal ArticleDOI
Kai Salomaa1
TL;DR: Using the scheduling theory approach as introduced by Gonczarowski and Warmuth (1985), this work proves a pumping property of 2- context-free languages and shows that the hierarchy of k-context- free languages is strict up to level three.

2 citations