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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Tree Transducers, L Systems, and Two-Way Machines
TL;DR: A relationship between parallel rewriting systems and two-way machines is investigated, finding restrictions on the “copying power” of these devices endow them with rich structuring and give insight into the issues of determinism, parallelism, and copying.
Journal ArticleDOI
Monadic Thue systems
TL;DR: The syntactic structure of sets of ancestors and sets of descendants is considered, as well as that of unions of congruence classes, taken over (infinite) context-free languages or regular sets.
Journal ArticleDOI
TOL systems and languages
TL;DR: TOL languages form an infinite hierarchy with respect to “natural” complexity measures introduced in this paper, and are contained in the family of context-free programmed languages.
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Chains of full AFL's
TL;DR: For eachn, there is a class of full context-free AFL's whose partial ordering under inclusion is isomorphic to the natural partial ordering onn-tuples of positive integers.
Journal ArticleDOI
Pushdown machines for the macro tree transducer
Joost Engelfriet,Heiko Vogler +1 more
TL;DR: This work defines several pushdown machines of which the control is recursive without parameters, or even iterative, and which work on a generalized pushdown as storage, and characterize the n-fold composition of total deterministic macro tree transducers by recursive push down machines with an iterated push down as storage.
References
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