Decidability in the logic of subsequences and supersequences
Logic in Computer Science
2016-07-07 v1 Formal Languages and Automata Theory
Abstract
We consider first-order logics of sequences ordered by the subsequence ordering, aka sequence embedding. We show that the \Sigma_2 theory is undecidable, answering a question left open by Kuske. Regarding fragments with a bounded number of variables, we show that the FO2 theory is decidable while the FO3 theory is undecidable.
Cite
@article{arxiv.1510.03994,
title = {Decidability in the logic of subsequences and supersequences},
author = {Prateek Karandikar and Philippe Schnoebelen},
journal= {arXiv preprint arXiv:1510.03994},
year = {2016}
}