English

Detecting patterns in finite regular and context-free languages

Formal Languages and Automata Theory 2009-06-18 v1

Abstract

We consider variations on the following problem: given an NFA M and a pattern p, does there exist an x in L(M) such that p matches x? We consider the restricted problem where M only accepts a finite language. We also consider the variation where the pattern p is required only to match a factor of x. We show that both of these problems are NP-complete. We also consider the same problems for context-free grammars; in this case the problems become PSPACE-complete.

Keywords

Cite

@article{arxiv.0906.3220,
  title  = {Detecting patterns in finite regular and context-free languages},
  author = {Narad Rampersad and Jeffrey Shallit},
  journal= {arXiv preprint arXiv:0906.3220},
  year   = {2009}
}

Comments

9 pages

R2 v1 2026-06-21T13:14:24.475Z