English

An omega-power of a context-free language which is Borel above Delta^0_omega

Computational Complexity 2008-09-10 v1 Computer Science and Game Theory Logic in Computer Science Logic

Abstract

We use erasers-like basic operations on words to construct a set that is both Borel and above Delta^0_omega, built as a set V^\omega where V is a language of finite words accepted by a pushdown automaton. In particular, this gives a first example of an omega-power of a context free language which is a Borel set of infinite rank.

Keywords

Cite

@article{arxiv.0801.1783,
  title  = {An omega-power of a context-free language which is Borel above Delta^0_omega},
  author = {Jacques Duparc and Olivier Finkel},
  journal= {arXiv preprint arXiv:0801.1783},
  year   = {2008}
}

Comments

To appear in the Proceedings of the International Conference Foundations of the Formal Sciences V : Infinite Games, November 26th to 29th, 2004, Bonn, Germany, Stefan Bold, Benedikt L\"owe, Thoralf R\"asch, Johan van Benthem (eds.), College Publications at King's College (Studies in Logic), 2007