Two-element structures modulo primitive positive constructability
Rings and Algebras
2020-01-31 v2 Logic
Abstract
Primitive positive constructions have been introduced in recent work of Barto, Opr\v{s}al, and Pinsker to study the computational complexity of constraint satisfaction problems. Let be the poset which arises from ordering all finite relational structures by pp-constructability. This poset is infinite, but we do not know whether it is uncountable. In this paper, we give a complete description of the restriction of to relational structures on a two-element set; in particular, we prove that is a lattice. Finally, we use to present the various complexity regimes of Boolean constraint satisfaction problems that were described by Allender, Bauland, Immerman, Schnoor and Vollmer.
Cite
@article{arxiv.1905.12333,
title = {Two-element structures modulo primitive positive constructability},
author = {Manuel Bodirsky and Albert Vucaj},
journal= {arXiv preprint arXiv:1905.12333},
year = {2020}
}