Topic
Chomsky hierarchy
About: Chomsky hierarchy is a research topic. Over the lifetime, 601 publications have been published within this topic receiving 31067 citations. The topic is also known as: Chomsky–Schützenberger hierarchy.
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TL;DR: This comparison of k-limited and regulated ETOL systems considers regular control, which has not been considered by Watjen (1993), which is not included in this comparison.
4 citations
TL;DR: The Chomsky-Schutzenberger representation theorem is improved and it is shown that each context-free language L can be represented in the form L = h (D ∩ R), where D is a Dyck language, R is a strictly 3-testable language, and h is a morphism.
Abstract: In this paper, we obtain some refinement of representation theorems for context-free languages by using Dyck languages, insertion systems, strictly locally testable languages, and morphisms. For instance, we improved the Chomsky-Schutzenberger representation theorem and show that each context-free language L can be represented in the form L = h (D ∩ R), where D is a Dyck language, R is a strictly 3-testable language, and h is a morphism. A similar representation for context-free languages can be obtained, using insertion systems of weight (3, 0) and strictly 4-testable languages.
3 citations
18 Jun 2007
TL;DR: In this paper, a hierarchy of families between the Σ 2 and Δ 3 levels of the arithmetic hierarchy is presented, and the structure of the top five levels of this hierarchy is in some sense similar to the structure in the Chomsky hierarchy, while the bottom levels are reminiscent of the bounded oracle query hierarchy.
Abstract: We present a hierarchy of families between the Σ 2 and Δ 3 levels of the arithmetic hierarchy. The structure of the top five levels of this hierarchy is in some sense similar to the structure of the Chomsky hierarchy, while the bottom levels are reminiscent of the bounded oracle query hierarchy.
3 citations
01 Sep 1975
TL;DR: The unique extension property of this map extends to a homomorphism (uniquely) ~ : W~(X) ÷ A by induction as follows: (i) ~(x) = ~ (x) for each xEX (2) ~ (~(e I ..... en)) = ~A(~ (e l) ..... ~(en)).
Abstract: : X ÷ A. This map extends to a homomorphism (uniquely) ~ : W~(X) ÷ A by induction as follows: (i) ~(x) = ~(x) for each xEX (2) ~(~(e I ..... en)) = ~A(~(e l) ..... ~(en)). We can use this idea to define composition of assignments. Let XI, X 2, X 3 ~ X and ~i : Xl ÷ W~(X2) and ~2 : X2 ÷ W~(X3) then we define ~2 o el(X) : ~2(~l(X)). Because of the unique extension property it is not difficult to verify that "o" is associative.
3 citations