On when the union of two algebraic sets is algebraic

Fuente: arXiv
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Main Authors: Aichinger, Erhard, Behrisch, Mike, Rossi, Bernardo
Format: Preprint
Published: 2023
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author Aichinger, Erhard
Behrisch, Mike
Rossi, Bernardo
author_facet Aichinger, Erhard
Behrisch, Mike
Rossi, Bernardo
contents In universal algebraic geometry, an algebra is called an equational domain if the union of two algebraic sets is algebraic. We characterize equational domains, with respect to polynomial equations, inside congruence permutable varieties, and with respect to term equations, among all algebras of size two and all algebras of size three with a cyclic automorphism. Furthermore, for each size at least three, we prove that, modulo term equivalence, there is a continuum of equational domains of that size.
format Preprint
id arxiv_https___arxiv_org_abs_2309_00478
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle On when the union of two algebraic sets is algebraic
Aichinger, Erhard
Behrisch, Mike
Rossi, Bernardo
Rings and Algebras
Logic
08A40 (Primary) 08A62, 08B05, 08B10, 20F70 (Secondary)
In universal algebraic geometry, an algebra is called an equational domain if the union of two algebraic sets is algebraic. We characterize equational domains, with respect to polynomial equations, inside congruence permutable varieties, and with respect to term equations, among all algebras of size two and all algebras of size three with a cyclic automorphism. Furthermore, for each size at least three, we prove that, modulo term equivalence, there is a continuum of equational domains of that size.
title On when the union of two algebraic sets is algebraic
topic Rings and Algebras
Logic
08A40 (Primary) 08A62, 08B05, 08B10, 20F70 (Secondary)
url https://arxiv.org/abs/2309.00478