English

Permutations of context-free and indexed languages

Formal Languages and Automata Theory 2015-01-06 v2

Abstract

We consider the cyclic closure of a language, and its generalisation to the operators CkC^k introduced by Brandst\"adt. We prove that the cyclic closure of an indexed language is indexed, and that if LL is a context-free language then Ck(L)C^k(L) is indexed.

Cite

@article{arxiv.1412.5512,
  title  = {Permutations of context-free and indexed languages},
  author = {Tara Brough and Laura Ciobanu and Murray Elder},
  journal= {arXiv preprint arXiv:1412.5512},
  year   = {2015}
}

Comments

13 pages, 5 figures

R2 v1 2026-06-22T07:35:27.773Z