Varieties whose tolerances are homomorphic images of their congruences

Fuente: arXiv
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Main Authors: Czedli, Gabor, Kiss, Emil W.
Format: Preprint
Published: 2012
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author Czedli, Gabor
Kiss, Emil W.
author_facet Czedli, Gabor
Kiss, Emil W.
contents The homomorphic image of a congruence is always a tolerance (relation) but, within a given variety, a tolerance is not necessarily obtained this way. By a Maltsev-like condition, we characterize varieties whose tolerances are homomorphic images of their congruences (TImC). As corollaries, we prove that the variety of semilattices, all varieties of lattices, and all varieties of unary algebras have TImC. We show that a congruence n-permutable variety has TImC if and only if it is congruence permutable, and construct an idempotent variety with a majority term that fails TImC.
format Preprint
id arxiv_https___arxiv_org_abs_1204_2228
institution arXiv
publishDate 2012
record_format arxiv
spellingShingle Varieties whose tolerances are homomorphic images of their congruences
Czedli, Gabor
Kiss, Emil W.
Rings and Algebras
Primary 08A30. Secondary 08B05, 08A60, 06B10, and 20M99
The homomorphic image of a congruence is always a tolerance (relation) but, within a given variety, a tolerance is not necessarily obtained this way. By a Maltsev-like condition, we characterize varieties whose tolerances are homomorphic images of their congruences (TImC). As corollaries, we prove that the variety of semilattices, all varieties of lattices, and all varieties of unary algebras have TImC. We show that a congruence n-permutable variety has TImC if and only if it is congruence permutable, and construct an idempotent variety with a majority term that fails TImC.
title Varieties whose tolerances are homomorphic images of their congruences
topic Rings and Algebras
Primary 08A30. Secondary 08B05, 08A60, 06B10, and 20M99
url https://arxiv.org/abs/1204.2228