This paper is a continuation of the study of topological properties of omega context free languages (!-CFL). We proved in (Topological properties of omega context free languages, Theoretical Computer Science, 262 (1-2) (2001) 669-697) that the class of !-CFL exhausts the ΓΏnite ranks of the Borel hie
Borel hierarchy and omega context free languages
β Scribed by Olivier Finkel
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 214 KB
- Volume
- 290
- Category
- Article
- ISSN
- 0304-3975
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β¦ Synopsis
We give in this paper additional answers to questions of Lescow and Thomas (A decade of
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We extend the well-known notions of ambiguity and of degrees of ambiguity of ΓΏnitary context free languages to the case of omega context free languages (!-CFL) accepted by B uchi or Muller pushdown automata. We show that these notions may be deΓΏned independently of the B uchi or Muller acceptance co
The Green function of an arbitrary, finitely supported random walk on a discrete group with context-free word problem is algebraic. It is shown how this theorem can be deduced from basic results of formal language theory. Context-free groups are precisely the finite extensions of free groups.