Full AFLs and nested iterated substitution
TLDR
A superAFL is a family of languages closed under union with unitary sets, intersection with regular sets, and nested iterated substitution and containing at least one nonunitary set containing all context-free languages.Abstract:
A superAFL is a family of languages closed under union with unitary sets, intersection with regular sets, and nested iterated substitution and containing at least one nonunitary set Every superAFL is a full AFL containing all context-free languages If L is a full principal AFL, then Ŝ∞(L), the least superAFL containing L, is full principal If L is not substitution closed, the substitution closure of L is properly contained in Ŝ∞(L) The indexed languages form a superAFL which is not the least superAFL containing the one-way stack languages If L has a decidable emptiness problem, so does Ŝ∞(L) IfDs is an AFA, L = L(Ds) and Dw is the family of machines whose data structure is a pushdown store of tapes of Ds, then L(Ds) = Ŝ∞(L) if, and only if, Ds is nontrivial If Ds is uniformly erasable and L(Ds) has a decidable emptiness problem, then it is decidable if a member of Dw is finitely nestedread more
Citations
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Proceedings Article
A Fuzzy Approach to Erroneous Inputs in Context-Free Language Recognition
TL;DR: This paper introduces a generalization of fuzzy context-free grammars to model the situation of malting a finite choice out of an infinity of possible grammatical errors during each context- free derivation step and characterizes the generating capacity of these fuzzycontext-free K-grammars.
Book ChapterDOI
Iterated Length-Preserving Rational Transductions
TL;DR: The purpose of this paper is the study of the smallest family of transduction containing length-preserving rational transductions and closed under union, composition and iteration, and gives several characterizations of this class using restricted classes of length- Preserving transduction.
Journal Article
Fuzzy Context-Free Languages. Part 1: Generalized Fuzzy Context-Free Grammars
TL;DR: The generating power of fuzzy context-free K-grammars is investigated, and it is shown that under minor assumptions on the parameter K, the family of languages generated by fuzzy Context-free Grammars possesses closure properties very similar to those of thefamily of ordinary context- free languages.
Journal ArticleDOI
Iterated pushdown automata and sequences of rational numbers
TL;DR: This method leads to new decidability results about integer sequences and reduces some equality problems for sequences of rational numbers to the equivalence problem for deterministic automata of level k.
Proceedings Article
Towards Robustness in Parsing -- Fuzzifying Context-Free Language Recognition
TL;DR: This work discusses the concept of robustness with respect to parsing or recognizing a context-free language and considers a robust version of Cocke-Youger-Kasami's algorithm and a robust kind of recursive descent recognizer.
References
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Journal ArticleDOI
Indexed Grammars—An Extension of Context-Free Grammars
TL;DR: A new type of grammar for generating formal languages, called an indexed grammar, is presented, and the class of languages generated by indexed grammars has closure properties and decidability results similar to those for context-free languages.
Proceedings ArticleDOI
Grammars with macro-like productions
TL;DR: Two new classes of grammars based on programming macros are studied, one of which is IO but not OI and the other OI but not IO, showing that neither class contains the other.
Journal ArticleDOI
One-way stack automata
TL;DR: A number of operations which either preserve sets accepted by one-way stack automata or preserve setsaccepted by deterministic one- way stack Automata are presented.
Journal ArticleDOI
Checking automata and one-way stack languages
TL;DR: The quasi-real-time one- way stack languages are not a full AFL but are a proper subAFL of the one-way stack languages, which properly include the stack languages.