Conservative Extensions in Guarded and Two-Variable Fragments
Logic in Computer Science
2017-05-30 v1
Abstract
We investigate the decidability and computational complexity of (deductive) conservative extensions in fragments of first-order logic (FO), with a focus on the two-variable fragment FO and the guarded fragment GF. We prove that conservative extensions are undecidable in any FO fragment that contains FO or GF (even the three-variable fragment thereof), and that they are decidable and 2\ExpTime-complete in the intersection GF of FO and GF.
Cite
@article{arxiv.1705.10115,
title = {Conservative Extensions in Guarded and Two-Variable Fragments},
author = {Jean Christoph Jung and Carsten Lutz and Mauricio Martel and Thomas Schneider and Frank Wolter},
journal= {arXiv preprint arXiv:1705.10115},
year = {2017}
}
Comments
Full version of paper accepted at ICALP 2017