Mal'cev products of rings satisfying xn≈ x and idempotent semirings
Abstract
Let Rn be the variety of rings satisfying xneqid x, where n≥2, and let W be a variety of idempotent semirings with commutative addition. The equality Rn∘W=Rn∨W holds, and this variety has subvariety lattice L(Rn)× L(W). Its subdirectly irreducible members that are not additively idempotent have exactly one nontrivial ring component, which is a finite field. Such a member is determined by this field and an idempotent semiring with a multiplicative identity; a separation condition on unary polynomial functions of the latter characterizes subdirect irreducibility. Every subvariety has a finite identity basis. A four-element semiring generates a variety with subdirectly irreducible members of unbounded cardinality. The results extend the Mal'cev product theorem of Wang and Shao from the absorption subvariety to arbitrary W≤Slp.
Related
- The variety generated by all additively idempotent semirings of order four
- Congruence-simple multiplicatively idempotent semirings and multiplicative divisibility
- Two-element factors and finite bases for additively idempotent semirings
- The Finite Basis Problem for Multiplicatively Idempotent Semirings
- The finite basis problem for additively idempotent semirings of order four, IV
BibTeX
@misc{wang2026malcev,
title = {{Mal'cev products of rings satisfying $x^n\approx x$ and idempotent semirings}},
author = {Aifa Wang and Lili Wang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.12188},
eprint = {2610.12188},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.12188},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Mal'cev products of rings satisfying x^n≈ x and idempotent semirings
AU - Aifa Wang
AU - Lili Wang
PY - 2026
DA - 2026/10/08
PB - arXiv
DO - 10.48550/arxiv.2610.12188
UR - https://arxiv.org/abs/2610.12188
AB - Let Rn be the variety of rings satisfying x^neqid x, where n≥2, and let W be a variety of idempotent semirings with commutative addition. The equality Rn∘W=Rn∨W holds, and this variety has subvariety lattice L(Rn)× L(W). Its subdirectly irreducible members that are not additively idempotent have exactly one nontrivial ring component, which is a finite field. Such a member is determined by this field and an idempotent semiring with a multiplicative identity; a separation condition on unary polynomial functions of the latter characterizes subdirect irreducibility. Every subvariety has a finite identity basis. A four-element semiring generates a variety with subdirectly irreducible members of unbounded cardinality. The results extend the Mal'cev product theorem of Wang and Shao from the absorption subvariety to arbitrary W≤Slp.
ER -