Inclusion of Unambiguous RE#s is NP-Hard
Computational Complexity
2011-11-03 v1
Abstract
We show that testing inclusion between languages represented by regular expressions with numerical occurrence indicators (RE#s) is NP-hard, even if the expressions satisfy the requirement of "unambiguity", which is required for XML Schema content model expressions.
Keywords
Cite
@article{arxiv.1111.0422,
title = {Inclusion of Unambiguous RE#s is NP-Hard},
author = {Pekka Kilpeläinen},
journal= {arXiv preprint arXiv:1111.0422},
year = {2011}
}
Comments
2 pages; unpublished; "Unambiguity" is also known as "weak determinism"; The paper actually shows the co-NP-hardness of the problem