Showing papers on "Indexed language published in 1992"
TL;DR: This paper gives a progression of automata and shows that it corresponds exactly to the language hierarchy defined with control grammars, the first member of which is context-free languages.
63 citations
28 Jun 1992
TL;DR: It is shown that the class of string languages generated by linear context-free rewriting systems is equal to theclass of output languages of deterministic tree-walking transducers.
Abstract: We show that the class of string languages generated by linear context-free rewriting systems is equal to the class of output languages of deterministic tree-walking transducers. From equivalences that have previously been established we know that this class of languages is also equal to the string languages generated by context-free hypergraph grammars, multicomponent tree-adjoining grammars, and multiple context-free grammars and to the class of yields of images of the regular tree languages under finite-copying top-down tree transducers.
44 citations
TL;DR: It is proved in this note that the class of all languages recognized by 2pfa's is strictly included in theclass of all deterministic context-sensitive languages.
19 citations
TL;DR: It is shown that a hierarchy of non-context-free languages, called control language hierarchy (CLH), generated by control grammars can be recognized in polynomial time.
15 citations
Proceedings Article•
30 Nov 1992TL;DR: Here it is shown that formal languages too can be specified by Harmonic Grammars, rather than by conventional serial rewrite rule systems.
Abstract: Basic connectionist principles imply that grammars should take the form of systems of parallel soft constraints defining an optimization problem the solutions to which are the well-formed structures in the language. Such Harmonic Grammars have been successfully applied to a number of problems in the theory of natural languages. Here it is shown that formal languages too can be specified by Harmonic Grammars, rather than by conventional serial rewrite rule systems.
9 citations
TL;DR: The main result is that pre-NTS grammars have a decidable equivalence problem.
Abstract: Pre-NTS languages have been introduced together with NTS languages by Boasson and Senizergues. In this paper we study the pre-NTS grammars. Our main result is that pre-NTS grammars have a decidable equivalence problem.
7 citations
TL;DR: It is shown that the recognition problem for tree adjoining languages can be solved by a concurrent read, concurrent write parallel random-access machine (CRCW PRAM) inO(logn) time using polynomially many processors.
Abstract: A parallel algorithm is presented for recognizing the class of languages generated by tree adjoining grammars, a tree rewriting system which has applications in natural language processing. This class of languages is known to properly include all context-free languages; for example, the noncontext-free sets {a
n
b
n
c
n
} and {ww} are in this class. It is shown that the recognition problem for tree adjoining languages can be solved by a concurrent read, concurrent write parallel random-access machine (CRCW PRAM) inO(logn) time using polynomially many processors. Thus, the class of tree adjoining languages is inAC
1 and hence inNC. This extends a previous result for context-free languages.