English

It Is NL-complete to Decide Whether a Hairpin Completion of Regular Languages Is Regular

Formal Languages and Automata Theory 2011-01-26 v1 Computational Complexity

Abstract

The hairpin completion is an operation on formal languages which is inspired by the hairpin formation in biochemistry. Hairpin formations occur naturally within DNA-computing. It has been known that the hairpin completion of a regular language is linear context-free, but not regular, in general. However, for some time it is was open whether the regularity of the hairpin completion of a regular language is is decidable. In 2009 this decidability problem has been solved positively by providing a polynomial time algorithm. In this paper we improve the complexity bound by showing that the decision problem is actually NL-complete. This complexity bound holds for both, the one-sided and the two-sided hairpin completions.

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Cite

@article{arxiv.1101.4824,
  title  = {It Is NL-complete to Decide Whether a Hairpin Completion of Regular Languages Is Regular},
  author = {Volker Diekert and Steffen Kopecki},
  journal= {arXiv preprint arXiv:1101.4824},
  year   = {2011}
}