Comer Schemes, Relation Algebras, and the Flexible Atom Conjecture

Fuente: arXiv
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Autores principales: Alm, Jeremy F., Andrews, David A., Levet, Michael
Formato: Preprint
Publicado: 2019
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author Alm, Jeremy F.
Andrews, David A.
Levet, Michael
author_facet Alm, Jeremy F.
Andrews, David A.
Levet, Michael
contents In this paper, we consider relational structures arising from Comer's finite field construction, where the cosets need not be sum free. These Comer schemes generalize the notion of a Ramsey scheme and may be of independent interest. As an application, we give the first finite representation of $34_{65}$. This leaves $33_{65}$ as the only remaining relation algebra in the family $N_{65}$ with a flexible atom that is not known to be finitely representable. Motivated by this, we complement our upper bounds with some lower bounds. Using a SAT solver, we show that $33_{65}$ is not finitely representable on fewer than $24$ points, and that $33_{65}$ does not admit a cyclic group representation on fewer than $120$ points. We also employ a SAT solver to show that $34_{65}$ is not representable on fewer than $24$ points.
format Preprint
id arxiv_https___arxiv_org_abs_1905_11914
institution arXiv
publishDate 2019
record_format arxiv
spellingShingle Comer Schemes, Relation Algebras, and the Flexible Atom Conjecture
Alm, Jeremy F.
Andrews, David A.
Levet, Michael
Logic
Combinatorics
Number Theory
03G15
In this paper, we consider relational structures arising from Comer's finite field construction, where the cosets need not be sum free. These Comer schemes generalize the notion of a Ramsey scheme and may be of independent interest. As an application, we give the first finite representation of $34_{65}$. This leaves $33_{65}$ as the only remaining relation algebra in the family $N_{65}$ with a flexible atom that is not known to be finitely representable. Motivated by this, we complement our upper bounds with some lower bounds. Using a SAT solver, we show that $33_{65}$ is not finitely representable on fewer than $24$ points, and that $33_{65}$ does not admit a cyclic group representation on fewer than $120$ points. We also employ a SAT solver to show that $34_{65}$ is not representable on fewer than $24$ points.
title Comer Schemes, Relation Algebras, and the Flexible Atom Conjecture
topic Logic
Combinatorics
Number Theory
03G15
url https://arxiv.org/abs/1905.11914