DocumentCode
3263505
Title
An infinite hierarchy of context-free languages
Author
Greibach, Sheila A.
fYear
1967
fDate
18-20 Oct. 1967
Firstpage
32
Lastpage
36
Abstract
By generalizing the notions of a one counter machine and of a finite turn pushdown store automaton, it is possible to define an omega 2-hierarchy of families of context-free languages such that each subfamily is infinite, closed under union, concatenation and closure, homomorphism, intersection with regular sets and inverse homomorphism and reversal. Each subfamily can be characterized in a manner akin to the Chomsky-Schutzenberger characterization of the context-free languages. Whenever two subfamilies are incomparable it is undecidable whether a member of one belongs to the other.
Keywords
Automata; Counting circuits;
fLanguage
English
Publisher
ieee
Conference_Titel
Switching and Automata Theory, 1967. SWAT 1967. IEEE Conference Record of the Eighth Annual Symposium on
Conference_Location
Austin, TX, USA
Type
conf
DOI
10.1109/FOCS.1967.5
Filename
5397224
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